Kristen Stewart worried about Robert Pattinson?

Kristen Stewart is said to be worried about her Twilight co-star and rumoured boyfriend Robert Pattinson.

Rob, 24,  is said to be on the verge of a mental breakdown due to the constant spotlight on his personal life.

An insider told Look Magazine: “Kristen’s absolutely frantic about Rob. She’s never known him to get so upset.”

“He’s gone from obscurity to being one of the biggest stars on the planet and the pressure he is under is unbelievable. She’s trying to keep his spirits up, but she’s worried he needs more support,” the source added.

It was reported earlier this week that Kristen was suggesting they take a break from big movies in favour of theatre work.