An Yves Saint Laurent dress belonging to Princess Grace was showcased at Yves Saint Laurent: The Retrospective at the Denver Art Museum from March 25 - July 8, 2012.
I was pretty excited to capture the first photo on top with my phone.
I suspect that the black flower piece is detachable and that Princess Grace is wearing the Yves Saint Laurent dress (or some variant of it) in the bottom two photos at two separate events in the 1960s (a charity event in 1965, and Royal Ascot in 1966, respectively).
Mother of pearl! This is so freaking great!