Patrick Dempsey is going from doctor to action hero.
The actor, who plays Derek "McDreamy" Shepherd on "Grey's Anatomy," has signed on to star in "Transformers 3," a rep for Paramount Pictures, the studio behind the film, confirmed to Access Hollywood on Tuesday.
Patrick will play the boss of Mikaela Banes, played by brunette beauty Megan Fox.
The movie also stars Shia LaBeouf as Sam Witwicky.
Breakout "Hangover" star Ken Jeong is also reportedly on board.
"Transformers 3" is expected to begin filming later this month and will be released in Summer 2011.
According to Entertainment Weekly, which first reported the news, the movie will film in Africa, Russia, China and the U.S.
Patrick's character is said to be very important to the drama in the third film.
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