Banks and Mann to star in "Thinking"

Actress Elizabeth Banks poses at the premiere of the movie ''I Love You, Man'' at the Mann's Village theatre in Los Angeles March 17, 2009.

LOS ANGELES (Hollywood Reporter) - Actresses Leslie Mann and Elizabeth Banks will explore the comic side of bad relationships in "What Was I Thinking?," a movie based on the nonfiction book of the same name.

New Line has picked up the project.

In the book, Barbara Davilman and Liz Dubelman compiled 58 bad-boyfriend stories.

Producer Lynda Obst enlisted Susanna Fogel and Joni Lefkowitz, who wrote the Sarah Jessica Parker HBO pilot "The Washingtonienne," to come up with a movie story.

The film will revolve around a woman who gets dumped during her engagement party. Her friends spring into action and whisk her away on a ski trip for healing and hedonism. Threading through their adventures on the trip are four flashbacks dealing in "worst ex-boyfriend" tales.

"It's a story of how women help each other," said Obst. "And we do that by telling stories." Obst also described the project as "a girls' Apatow movie," referring to filmmaker Judd Apatow's signature male-centric comedy style.

Mann (who happens to be married to Apatow) would play a woman who dates a lot but never seems to have serious relationships, while Banks is a woman on the rebound. Two other lead female parts have yet to be cast.

Mann co-stars in the Zac Efron-toplined "17 Again." After that, she appears in Apatow's "Funny People," as well as Robert Rodriguez's "Short" and "I Love You Phillip Morris," starring Jim Carrey and Ewan McGregor.

Banks recently starred in the comedies "Zack and Miri Make a Porno" and "Role Models," as well as the horror movie "The Uninvited."

(Editing by Sheri Linden at Reuters)