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US President Barack Obama, former US president George W. Bush with First Lady Michelle Obama and former First Lady Laura Bush arrive for the unveiling of the Bush's portraits on Thursday in the East Room of the White House in Washington, DC.

Carolyn Kaster / AP

Former President George W. Bush unveils his portrait in the East Room of the White House in Washington on Thursday.

Mandel Ngan / AFP - Getty Images

Former US president George W. Bush and his wife Laura Bush speak during the unveiling of their portraits on Thursday in the East Room of the White House in Washington, DC.

Mandel Ngan / AFP - Getty Images

Former US President George H.W. Bush and his wife Barbara arrive for the portrait unveiling of former US president George W. Bush and his wife Laura Bush in the East Room of the White House in Washington, DC.

Charles Dharapak / AP

President George W. Bush's daughters Jenna and Barbara have their photo taken in the East Room at the White House in Washington on Thursday prior to the unveiling of President Bush's official portrait.

This report from NBC's Shawna Thomas includes some of the humor the two presidents shared at the event:

“When the British burned the White House ... in 1814, Dolly Madison famously saved this portrait of the first George W. Now Michelle, if anything happens, there's your man,” Bush joked. (During her speech, First Lady Michelle Obama promised she’d go straight for his portrait.)

And former President Bush didn’t spare the current president: “I am also pleased, Mr. President, that when you are wandering these halls as you wrestle with tough decisions, you will now be able to gaze at this portrait and ask: What would George do?

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Kevin Lamarque / Reuters

President Barack Obama presents a birthday cake to Bloomberg White House reporter Julianna Goldman as she blows out the candle aboard Air Force One during the flight to Washington from Afghanistan May 2, 2012.

Which was more surprising? Being flown to Afghanistan in the middle of the night aboard Air Force One? Or having the President of the United States honor your birthday?

Win Mcnamee / Getty Images

President Barack Obama acts out a part of the story while reading from the book "Where the Wild Things Are" with first lady Michelle Obama (L) and his daughter Sasha (R) during the White House Easter Egg Roll on the South Lawn of the White House on April 9 in Washington, D.C.

Kevin Lamarque / Reuters

President Obama smiles at the Easter Bunny during the 2012 White House Easter Egg Roll on April 9 on the South Lawn

Larry Downing / Reuters

First lady Michelle Obama (R) and her children, Sasha (C) and Malia cheer at the 2012 White House Easter Egg Roll on the South Lawn of the White House in Washington on April 9 in Washington D.C.

Jim Lo Scalzo / EPA

Visitors participate in the 2012 White House Annual Easter Egg Roll on the South Lawn of the White House on April 9. More than 35,000 people are expected at the event.

Brendan Smialowski / AFP - Getty Images

President Obama does pushups during basketball shooting drills during the White House Easter Egg Roll on the South Lawn on April 9. The annual event includes sporting activities and games along with the traditional easter egg roll.

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Pablo Martinez Monsivais / AP

President Barack Obama greets members of the military and their families during his departure at Osan Air Base, South Korea, Tuesday, March, 27, 2012. Obama is returning to Washington after attending the Nuclear Security Summit in Seoul.

Jewel Samad / AFP - Getty Images

President Barack Obama greets U.S. soldiers and family members before boarding Air Force One at Osan Air Base in Osan outside Seoul on March 27, 2012 after attending the 2012 Seoul Nuclear Security Summit.

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Pablo Martinez Monsivais / AP

U.S. President Barack Obama, left, and Russian President Dmitry Medvedev stand together at the end of a bilateral meeting at the Nuclear Security Summit in Seoul, South Korea, Monday, March 26, 2012.

Pablo Martinez Monsivais / AP

U.S. President Barack Obama, left, chats with Russian President Dmitry Medvedev during a bilateral meeting at the Nuclear Security Summit in Seoul, South Korea, Monday, March, 26, 2012.

The leaders of the two super-powers and former Cold war foes met in South Korea to discuss the state of nuclear arms with other world leaders.

At the very beginning of the photo opportunity after the the bilateral meeting between them, the two leaders, seemingly unaware of a live microphone, had this hushed exchange about missile defense:

Obama: On all these issues, but particularly missile defense, this, this can be solved but it's important for him to give me space.

Medvedev: Yeah, I understand. I understand your message about space. Space for you...

Obama: This is my last election. After my election I have more flexibility

Medvedev: I understand. I will transmit this information to Vladmir.

White House spokesman Ben Rhodes responded to reporters' inquiries about the conversation saying:

Ben Rhodes: "The United States is committed to implementing our missile defense system, which we've repeatedly said is not aimed at Russia. However, given the longstanding difference between the US and Russia on this issue, it will take time and technical work before we can try to reach an agreement. Since 2012 is an election year in both countries, with an election and leadership transition in Russia and an election in the United States, it is clearly not a year in which we are going to achieve a breakthrough. Therefore, President Obama and President Medvedev agreed that it was best to instruct our technical experts to do the work of better understanding our respective positions, providing space for continued discussions on missile defense cooperation going forward."

Story: Obama says the U.S has a 'moral obligation' to lead efforts to reduce nuclear stockpiles

Story: Obama vows to pursue further nuclear cuts with Russia

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Barack and Michelle Obama stand alongside British Prime Minister David Cameron and his wife, Samantha as they arrive for a State Dinner on March 14.

Alex Wong / Getty Images

President Barack Obama accidentially steps on First lady Michelle Obama's dress as they walk onto the North Portico before the arrival of British Prime Minister David Cameron and his wife Samantha.

Alex Wong / Getty Images

President Barack Obama proposes a toast as he hosts British Prime Minister David Cameron and his wife Samantha Cameron for a state dinner at the South Lawn of the White House on Wednesday night.

Susan Walsh / AP

The White House is awash with color for the State Dinner for British Prime Minister David Cameron on Wednesday night.

Related stories:

• Crispy halibut, bison on White House state dinner menu 
• See slideshow of first lady fashion hits and misses: State Dinner edition
• More photos of Michelle Obama's effortless style in our slideshow
• Michelle Obama wears Marchesa to state dinner

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Pablo Martinez Monsivais / AP

President Barack Obama meets with British Prime Minister David Cameron in the Oval Office of the White House, March 14, 2012.

Doug Mills / Pool via Reuters

President Barack Obama and British Prime Minister David Cameron talk during their Oval Office meeting at the White House, March, 14, 2012.

As a photographer, covering the White House often means crowding with a pool of journalists into a room for a very brief time - sometimes just a few minutes, and trying to capture the mood of a meeting between two world leaders before the real meeting actually begins. New York Times photographer Doug Mills, who was part of the White House pool today, captures the view from the other side. Can you imagine trying to act normal in front of all the cameras and microphones? I think both sides have an equal challenge.

Mills' colleague, Stephen Crowley, videotaped his experience during one of these pool spray events at the Oval office. You can see it on the New York Times' website.

See more images from Obama's fourth year in office in our slideshow below.

Slideshow: As it happens: Obama's fourth year in office

Cliff Owen / AP

The president's fourth year at the White House in pictures — follow along as it happens.

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Jim Watson / AFP - Getty Images

President Barack Obama shares a laugh with British Prime Minister David Cameron as they take in March Madness at the University of Dayton Arena on March 13.

Jim Watson / AFP - Getty Images

President Barack Obama and British Prime Minister David Cameron eat hot dogs as they sit in the stands at University of Dayton Arena in Dayton.

Basketball fan-in-chief President Barack Obama is giving British Prime Minister David Cameron a front-row seat to March Madness, taking his European partner to an election swing state for an NCAA tournament basketball game.

Amid cheers, the two leaders entered the University of Dayton Arena on Tuesday for a "First Four" matchup between Mississippi Valley State and Western Kentucky, a gesture of goodwill during Cameron's official visit to the United States and a way for an incumbent president to reach sports fans in an election year.

-- The Associated Press

Related links:

• President Obama, British PM on hand for the First Four
• Obama’s Final Four: Kentucky, Ohio St., Mizzou, UNC

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Slideshow: As it happens: Obama's fourth year in office

Cliff Owen / AP

The president's fourth year at the White House in pictures — follow along as it happens.

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Pablo Martinez Monsivais / AP

President Barack Obama leads guests to a toast as he hosts a dinner for members of the U.S. military who served in Iraq in the East Room of the White House in Washington, Wednesday, Feb., 29, 2012.

Joshua Roberts / Reuters

U.S. President Barack Obama speaks during a dinner on Wednesday night.

Slideshow: US troops leave Iraq

See images from the U.S. withdraw from Iraq at the end of 2010 and 2011.

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AP reports: The president who opposed the Iraq war from its outset thanked those who fought its battles by sitting down to a candlelit meal with a small cross section of the million-plus who served there over the past nine years.

Looking out over a sea of dress uniforms sparkling with medals attesting to years of wartime strife, Obama told the gathering: "In a culture that celebrates fame and fortune, yours are not necessarily household names. You are something more: the patriots who served in our name. And after nearly nine years in Iraq, tonight is an opportunity to express our gratitude and to say once more, welcome home."

Brendan Smialowski / Getty Images

U.S. President Barack Obama speaks in the State Dining Room of the White House, Feb. 26, in Washington, D.C. President Obama and first lady Michelle Obama hosted 2012 Governors Dinner which coincides with the yearly meeting of the National Governors Association meeting in Washington, D.C.

Brendan Smialowski / Getty Images

U.S. President Barack Obama makes a toast after speaking in the State Dining Room of the White House, Feb. 26.

The president and First Lady Michelle Obama hosted a black tie dinner for governors Sunday as part of the National Governors Association winter meeting in Washington. The president said governors have some of the hardest jobs in politics; they are expected to be accountable and yield practical results for their states.

Obama said he and the governors wouldn't always agree on every issue but he looked forward to greater collaboration going forward. He offered a toast to the governors for their outstanding work and "to the spouses who put up with us."

-- Reported by the Associated Press

Related content: PhotoBlog posts featuring Barack Obama

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Brendan Smialowski / Getty Images

Vice President Joseph R. Biden, left, and New Jersey Governor Chris Christie (R-NJ), right, toast in the State Dining Room of the White House Feb. 26, in Washington, D.C.

Pablo Martinez Monsivais / AP

B.B. King, left, Buddy Guy and Warren Haynes, right, perform during the White House Music Series saluting Blues Music in recognition of Black History Month, Tuesday, Feb. 21, 2012, in the East Room of the White House in Washington.

Win McNamee / Getty Images

President Barack Obama speaks on Tuesday night.

Chris Kleponis / Reuters

Blues legend B.B. King signals approval while performing on Tuesday night.

AP reports: At a concert tonight at the White House marking Black History Month and celebrating the blues, President Obama again took the mic. He was challenged by the musicians on stage to follow up his Al Green "I'm So In Love With You" performance, "You done started something, and you gotta keep it up now." After initially laughing off the offer, the President took the microphone and sang several lines of "Sweet Home Chicago" from his spot in the front row. He tried handing the mic back more than once, but continued singing, even alternating lines with BB King.

The concert featured music legends and contemporary major artists, including King and Mick Jagger, as a celebration of Blues music and in recognition of Black History Month. The concert, airing next week on PBS, is part of the "In Performance at the White House" series.

Win McNamee / Getty Images

Shemekia Copeland (L) and Susan Tedeschi (R) perform with an all-star cast on Tuesday night.

Related story:

• Michelle Obama tells teens at blues' lesson president didn't start at top