Washington, Nov 7 (ANI): Twilight stars Robert Pattinson and Kirsten Stewart prefer to keep their relationship secret, say sources.

The two actors have been constantly ducking rumours of their romance.

"Rob and Kristen are funny because they're so super secretive, even with their closest friends in the cast, they're very cryptic," Fox News quoted a source as saying.

"They're very boring people. Very low key and don't discuss their relationship," the source added.

The sources also revealed that Pattinson's off-screen romance with Stewart caused major friction with fellow Twilight star Nikki Reed, who started dating Pattinson late last year.

"After the first Twilight wrapped, when Rob and Nikki were together and no one was a megastar yet, you could still see the sparks between Kristen and Rob even though they were each in their respective relationships... they always had this really intense, magnetic chemistry. So Nikki was the one to get hurt," said a source.

However, Reed has now found herself another beau Paris Hilton's former fiance.

"Nikki was really in love with Rob, but we're all scared to bring it up now. It's something we just don't talk about," said the source.

"Everyone is relieved she's with Paris [Latsis, Paris Hilton's former fiance] because he is an amazing boyfriend to her. She's happy and she's really found someone that she can lean on through all the media hype surrounding the series," the source added. (ANI)