Cameron Diaz rocked curly hair and a robe yesterday on the Atlanta set of What to Expect When You're Expecting. She was joined between scenes by costars Whitney Port and Cheryl Cole, who's making her Hollywood debut after her rather public departure from The X-Factor earlier this Summer. Interestingly, Cheryl's role is actually that of a talent show judge. The movie making seems to have inspired Cheryl to start tweeting. She wrote earlier this morning, "It's me CC! Where my soldiers at. . . ? I can't believe what my fingers are doing, but yes, I'm tweeting! So here goes." Today is Cameron's 39th birthday — and we're celebrating with a look at Cameron Diaz's hottest bikini moments! She got an early birthday present over the weekend, when her Bad Teacher crossed the $200 million mark at the box office.