Robert was said joining Kristen on her movie set 'because Kristen has a real risque part' with Viggo Mortensen and he 'wants to make sure that it's all pretend from the start and finish of the film.'
Robert Pattinson might share the same nature as his character in "Twilight" movie, Edward Cullen. While Edward desperately wants to always be with Kristen Stewart's Bella Swan to protect her from harm, Robert tried to accompany Kristen on her movie set because he wanted to make sure Kristen won't cheat on him with her "On the Road" co-star Viggo Mortensen.
"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!" an insider told Hollywood Life. "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."
The insider further claimed Robert wasn't happy that Kristen agreed to take the role of sexually promiscuous young Marylou Moriarty. "He didn't like that Kristen was even considering taking this role. He understands that she doesn't want to be known as just Bella from 'Twilight', and he's doing the same thing with his own career, but he didn't take on a role as risque as hers!" the insider went on.
And Viggo, who is 21 years older that Kristen, has reportedly caused a rift between the 20-year-old beauty and Robert. "He's very jealous," the insider stated. "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."
The source continued, "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."
Beside playing alongside Viggo Mortensen in upcoming movie "On the Road", which is slated for 2011 release, Kristen Stewart will also be seen starring opposite two other heartthrobs in the project: Garrett Hedlund, who will portray her troubled drifter husband, and Sam Riley.