(Cover) - EN Showbiz - Jennifer Aniston has been described as a "crazy diva sex machine".

The 42-year-old actress is co-starring alongside Jason Bateman, Jason Sudeikis and Charlie Day in the upcoming comedy Horrible Bosses as a raunchy, oversexed dentist.

One of Jennifer's co-stars Lindsay Sloane, has revealed she was surprised by the blonde beauty's overtly sexual nature on set.

"I read the script and I was like, 'There's no way that sweet Jennifer Aniston is going to say these words and they're going to sound sexual and aggressive,' but then it was like, 'Whoa, she's like a crazy diva sex machine,'" she told E! Online "She ad-libbed a lot. Sometimes she would say things and after they would call cut, she would be like, 'I don't know. Isn't that taking it a little too far?' But then everyone loved it."

Charlie, who plays Dale, a dental assistant in the movie, says Jennifer was too raunchy at times. The actor who is the target of many of Jennifer's antics in the upcoming black comedy says the star would often be pulled up on her sexy behaviour.

"I think there were a couple of times we really had to rein her in. We were like, That's too raunchy," he laughed. (C) Cover Media