Just working with an ex can be an awkward experience, but how about filming sex scenes together? Cameron Diaz and Justin Timberlake put their friendship to the test for 'Bad Teacher' in what director Jake Kasdan said was the "most uncomfortable sex scene in history."

Diaz had a good sense of humor about the whole thing, but acknowledged that hooking up with an ex on-screen was a bizarre experience.

"Yes, yes. It was just [an] absurdity, a form of hilarity for all of us involved," she told PEOPLE. "We went to work that day and said, what time do we start being ridiculous? ... Eight o'clock? Perfect."

Katzen says the pair just brushed off the awkwardness and did their job with professionalism and lots of laughs.