Twilight star Robert Pattinson's apparent jealousy toward Kristen Stewart's co-star Viggo Mortensen is starting to create buzz for Kristen's new non-Twilight movie On the Road. Pattinson has been reportedly on the watch for the love scenes between Kristen Stewart and Viggo Mortensen, just to make sure that nothing is for real.

A source quoted by Holywoodlife.com claimed that Robert Pattinson's visits to Montreal, where Kristen Stewart shoots for the film, will be part of Pattinson's usual itinerary as the Twilight star wants to make sure that the sex scenes, which includes a threesome, is "all pretend."

Pattinson fears that New York City-born Mortessen will seduce Kristen away from his arms.

"[Robert Pattinson] 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!," said the source to the website. "

There are a lot of sex scenes including a threesome, and [Pattinson] wants to make sure that it's all pretend from the start and finish of the film."

Is Robert Pattinson paranoid? He was recently declared Glamour's Sexiest Man and remains one of the hottest male celebrities in Hollywood and in the whole world. Kristen Stewart has a lot to lose if she abandons Robert Pattinson for Viggo Mortessen.

Or perhaps, Pattinson just happen to have a lot of spare time as his movie Water for Elephants recently concluded filming in California.