MARY-KATE OLSEN'S COLORFUL NEW ROLE

Mary-Kate Olsen is still smokin'!The 21-year-old, who's guest starring on the Showtime comedy Weeds this season, has signed onto the stoner film The Wackness.The flick, written and directed by Jonathan Levine, follows the eccentric relationship between a drug dealer (Drake and Josh's Josh Peck) and his psychiatrist (Sir Ben Kingsley), who offers therapy sessions in exchange for marijuana. Mary-Kate will play the dread-headed pothead friend/'client' of Peck's character, which will mark her first on-screen under-the-influence performance ? she portrays a devout Christian on Weeds.X-Men's Famke Janssen, Olivia Thirlby of the now-defunct series Kidnapped, and Method Man also co-star.The Wackness starts filming this fall in New York City.Season three of Weeds premieres Monday, Aug. 13 at 10 p.m.By Joyce EngPhoto: Wireimage.com