Demi Moore and Michael Caine in
Flawless
Description from IMDB:
"...a diamond-heist thriller set in swinging 1960s London. Demi Moore plays Laura Quinn, a bright, driven and beautiful executive at the London Diamond Corporation who finds herself frustrated by a glass ceiling after years of faithful employment, as man after man is promoted ahead of her despite her greater experience. Michael Caine is Hobbs, the nighttime janitor at London Diamond who is virtually invisible to the executives that work there, but over the years has amassed a startling amount of knowledge about how the company runs. Hobbs has his own bone to pick with London Diamond. Observing Lauras frustration, he convinces her to help him execute an ingenious plan to steal a hefty sum in diamonds. But unbeknownst to Laura, Hobbs plans go even farther..."