OK! EXCLUSIVE: JT's Sexy Scenes with Cameron

On March 8, Justin Timberlake began filming Bad Teacher with his ex-girlfriend Cameron Diaz — and one scene calls for the two to talk dirty while passionately making out. Talk about awkward!

OK! NEWS: CAM DIAZ DISHES ON JT JOINING NEW COMEDY

Especially when Justin and Jessica Biel are falling in love all over again.

OK! NEWS: CAM DIAZ & EX JT GEAR UP FOR NEW ACTING GIG...TOGETHER

"She moved back into his Hollywood Hills place a couple of weeks ago," a source tells OK!. "Justin was a bit freaked out at first, but Jessica wouldn't take no for an answer.

OK! GALLERY: JUSTIN & JESSICA HANG NEAR HOME

"Justin has avoided making a commitment. She'd like a ring, and has left him over his refusal to commit a number of times. But they always get back together."

OK! NEWS: JUSTIN TIMBERLAKE AND JESSICA BIEL — FAMILY BONDING TIME