Makeup artist Allan "Whitey" Snyder applies makeup to Monroe on the set of 1953's "Gentlemen Prefer Blondes."
Monroe posing in a test photo taken by Snyder on the set of her final film, 1962's "Something's Got to Give."
"It's spectacular," said Martin Nolan of Julien's Auction House, who brought several of the photos going up for auction on March 31 to the TODAY studio Friday, and spoke to Matt Lauer. "He was involved with her on the set and off the set, Matt, so he had amazing, privileged access."
Many of the photos were taken in the 1940s and 1950s and show Monroe smiling, giving her all to the camera while on location for some of her well-known and lesser-known films. Reportedly, Snyder would photograph Monroe to calm her down when she was feeling jittery.
"The camera loved Marilyn Monroe, but Marilyn loved the camera," said Nolan. "When the camera was rolling she became Marilyn Monroe. She became distracted from her own issues and just played the role. She loved the camera."
See lots more images in this slideshow: Rare look at Marilyn Monroe.
Snyder applies Monroe's makeup on the set of 1960's "Let's Make Love."