But Seeff says Keaton's off-camera persona matched up with what she portrayed on-screen.
"You know when you see Diane in a movie and there’s this kind of personality, this bright-eyed innocence? When I worked with her, there was this same feeling, but underneath the innocence was such a smart woman. She had the wonderful ability to just be herself. She flowed from one thing to the other, so I just kept pace with her. It was a jewel of a session," he told Vanity Fair of photographing the actress.
For the past 45 years, Seeff has photographed (and filmed) some of Hollywood's biggest names and now, for the very first time, 50 of his never-before-seen images are available for purchase.
Christie's online auction, which closes Wednesday, features 50 silver gelatin prints including images of Carly Simon, Steve Jobs, Mick Jagger, Michael Jackson, Ray Charles, Tina Turner, Johnny Cash, The Band, Patti Smith, Robert Mapplethorpe, the Ramones, Steve Martin, John Belushi and more.
A year after photographing Keaton, Seeff worked with a 30-year-old Cher, who posed for him after walking into his Sunset Strip studio with a friend.
Another standout from Seeff's archive is an image of the late Whitney Houston, snapped in 1990, where the singer looks happy and carefree.