Elizabeth Banks In 'What To Expect When You're Expecting'

Back in March, Elizabeth Banks announced that she had a baby boy through a surrogate, marking an exciting new time in her life. Now, she'll take the journey to motherhood all over again -- this time, on film.

Banks has signed on to the star-studded cast of "What to Expect When You're Expecting," joining Cameron Diaz, Jennifer Lopez, Brooklyn Decker and Ed Helms in the Kirk Jones-directed big screen adaptation of the seminal parenting manual.

According to a press release from Lionsgate, Banks will play the "author of a children's book about breast feeding and owner of The Breast Choice boutique," who, adamant about her beliefs about motherhood, has her world turned upside when she gets pregnant herself.

Banks tweeted the news Monday afternoon, first hinting at the casting when she wrote, "Spent the morning standing around in my underwear with a nice group of strangers trying on bellies. Guess why."

Soon after, bursting at the seams with the news, Banks tweeted, "Joining J Lo, Cameron Diaz and the rest of the awesome cast of What To Expect When You're Expecting! Let's have babies together!"

Here's the full press release (via ComingSoon.net):

Lionsgate and the producers of the film adaptation of the worldwide bestselling book What to Expect When You're Expecting have announced that Elizabeth Banks (The 40-Year-Old Virgin, upcoming The Hunger Games) has been cast to star with Cameron Diaz, Jennifer Lopez, Brooklyn Decker and Anna Kendrick in the film, which stars shooting this summer for a May 11, 2012 release.

Banks' character is baby-crazy - the author of a children's book about breast feeding and owner of The Breast Choice boutique, she is militant in her beliefs about what makes a good mother until she gets pregnant for the first time.

Kirk Jones (Waking Ned Devine, Nanny McPhee) is directing the film, which was acquired from a script by Heather Hach and re-written by Shauna Cross (Whip It). The film is based on the book by Heidi Murkoff that has been on the New York Times bestseller list for over 500 weeks. Lionsgate has worldwide rights to the film.