Mary-Kate Olsen isn’t a little girl anymore.  Gone are the days of Full House and The Adventures of Mary-Kate and Ashley.  At 21 years old, Mary-Kate is beginning to take on more adult roles, and her latest role is sure to cause a stir.

In her upcoming movie, The Wackness, Mary-Kate locks lips with Ben Kingsley - a highly regarded actor only 42 years older than her!  In a recent interview, Kingsley said: “There is a very passionate scene in the film, which we filmed last week. It went extremely well and she was very focused. She was very good, very professional. She was quite wonderful.”

When Kingsley was asked whether he thought the film would stir up controversy, he said: “I’m sure it will. (Her character) is this great free spirit, you know, she is equally seducing so it is a level playing field.”

In the film, Kingsley plays the role of a therapist who strikes up a friendship with a teen drug dealer that gives up his pot in favor of therapy.  Mary-Kate is one of the dealer’s customers, who ends up engaging in a passionate kiss with Kingsley’s character.

To be fair, the kiss is brief and happens just once.  There is no long, on-going love affair, but Mary-Kate’s kiss is enough to trigger a quest for happiness in Kingsley’s character.  The two meet only this once in the film, and as did her on-screen character, Mary-Kate in real life left a brief, but lasting impression on Kingsley who said  “Mary-Kate has huge energy. She is very, very committed to her work.”

The Wackness was written and directed by Jonathan Levine, and also stars Olivia Thirlby, Josh Peck, Method Man, Famke Janssen, and Peter Conboy.  It is currently slated for a 2008 release.