May 7, 2012 at 8:40 AM ET
Cameron Diaz may not have known exactly what to expect on the set of her new film, "What to Expect When You're Expecting," but she did have a pretty good idea of what goes on in delivery rooms -- having been present for all three births of her sister's children.
"First, a C-section, which will change your life -- do not witness that!" she advised TODAY's Ann Curry Monday morning. "And then the vaginal birth, which will change your life, men -- do not look at it.... Stay behind the curtain."
"What to Expect" features Diaz and "Glee's" Matthew Morrison in one of five segments, which tell different stories and star actors including Jennifer Lopez, Anna Kendrick and Dennis Quaid.
Becoming an aunt, said Diaz, gave her some insight into being a mom (which she is not), which helped in making the movie. "I was very invested in it, the emotion there. You're waiting for the child to come," she said. "You're waiting to love this child and the intensity of that, all the fear, the terror, the excitement, the joy, everything that's present in the room at that moment is just so tangible, it's so beautiful, and we wanted to bring that to the (film's birth) scene."
Later on TODAY, "Glee" regular Matthew Morrison chatted with Kathie Lee Gifford and Hoda Kotb on his role in the film:
"What to Expect When You're Expecting" opens May 11. Check out the trailer:
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