Robert Pattinson Wants to Sit in on Kristen Stewart's Sex Scenes?!

Who knew that Robert Pattinson is a voyeur?

According to Hollywood Life, the Twilight heartthrob is intent on being present when his co-star and reported girlfriend, Kristen Stewart , films her sex scenes for the big-screen adaptation of Jack Kerouac's classic novel On the Road—because he's fearful that something might happen between Stewart and her co-star, 51-year-old Viggo Mortensen.

A source tells Hollywood Life,

“Rob plans on being on the set of On the Road, not because he has a role in the drama, but because Kristen has a real risque part! There are a lot of sex scenes including a threesome, and Rob wants to make sure that it’s all pretend from the start and finish of the film.”

Mortensen will be playing the role of Old Bull Lee, based on Naked Lunch author William S. Burroughs. Stewart, meanwhile, is playing Marylou, a part based on LuAnne Henderson, the teenage wife of Neal Cassady (referred to as Dean Moriarty in the book/movie). And given that Marylou will be portrayed as quite the sexual libertine in the movie, R-Pattz isn't taking any chances.

The source adds,

“He’s very jealous. Kristen told him she didn’t want him on the set because it would make her feel uncomfortable, but Rob said he’s going to be there. Especially now that her scenes are with Viggo, who is very very hot! Rob is free until filming begins on the next Twilight film, so he’s got all the time in the world to keep an eye on Kristen – and he will.”

The source further notes that Pattinson wasn't thrilled with Stewart taking the role in the first place, because of all the sexual subject matter.

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