Cameron Diaz is "thrilled" her ex-boyfriend Justin Timberlake has been cast as her love interest in new movie Bad Teacher - because his on-set antics are keeping her entertained.

The Charlie's Angels actress stars as a junior high school teacher who sets out to steal a colleague's boyfriend, played by Timberlake, in the comedy. Diaz dated the pop singer for almost four years until they split in 2007, and Timberlake has since found love with actress Jessica Biel. However, The Holiday star is excited to work alongside her former beau in the film, which also stars Molly Shannon and Jason Segel.

She tells Access Hollywood's Billy Bush, "We're thrilled to have him. He's the best person for the job. He's going to be hilarious. He's clearly a very talented comedian, look at his Saturday Night Live (skits). He's fantastic; he's going to be so great."

"We just had our first day of shooting yesterday with Jason. And we just laughed all day. It's so wonderful, I'm so excited." starpulse