Jessica Biel might want to give boyfriend Justin Timberlake's next film a miss because it features a sex scene between him and his ex, Cameron Diaz.

The pop star and actor started dating Biel shortly after ending his four-year romance with Diaz in 2007. The former lovers have stayed friends - and now they're going to be co-stars in comedy "Bad Teacher".

In the film, Diaz plays a woman trying to steal a colleague's boyfriend, played by Timberlake - and there's one racy scene Biel might want to make sure she's on set for.

Life & Style magazine has exclusively obtained a copy of the movie’s script, and in it, things get awfully steamy when the two exes' characters find themselves alone in a hotel room.

According to the publication, Justin's character begins "dry humping" Diaz's teacher and he gets "way too excited way too soon".

In the script, Timberlake's red-faced character says, "That was a mistake," to which his love interest responds, "That was fast."

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