Sir Ben Kingsley has revealed kissing Mary-Kate Olsen was "quite wonderful".The 63-year-old actor and the 21-year-old actress filmed a steamy love scene together for their new film 'The Wackness' in New York last week. Ben told the USA Today newspaper: "There is a very passionate scene in the movie, which we filmed last week."It went extremely well and she was very focused. She was very good, very professional. She was quite wonderful."In the movie - due out next year - the Oscar-winning actor plays a therapist who forms a friendship with a teenage drug dealer who trades marijuana for therapy sessions.Mary-Kate has been cast as one of the dealer's customers, who shares a kiss with the therapist, and despite her part being very small, Ben was impressed by her ability.He said: "It's for a few seconds and then we disappear and we never see each other again in the movie. But she is a trigger into my quest for happiness."She is this great free spirit, you know, she is equally seducing so it is a level playing field."Mary-Kate has huge energy. She is very, very committed to her work."Mary-Kate, the identical twin sister of Ashley, is embarking on a solo acting career.She had a small speaking part in 'Factory Girl' earlier this year but it was cut to a walk-on part.She has also landed a lead role in US TV show 'Weeds'.Mary-Kate's latest roles are noticeably different from the wholesome characters she and Ashley played on hit US TV series 'Full House'.After their run on the show ended, Mary-Kate and Ashley starred in a number of children's TV series and movies, including 'So Little Time' and 'New York Minute'.