Actress Kristen Stewart poses as she arrives for the world premiere of the video "My Valentine" directed by Paul McCartney in West Hollywood, California April 13, 2012. Photo: REUTERS/Mario Anzuoni

Kristen Stewart says people who "don't have the heart to back up their looks" are "ugly".

The 'Snow White and the Hunstman' star has looked up to many people in Hollywood who turned out to be "fake" when she met them.

Talking about beauty, she said: "If you don't have the heart to back up your looks, you are ugly.

"I've met so many people that I thought were so gorgeous and talented and amazing. And then you meet them for one second and you're like ... you are wearing a costume, you are a fake, you are so unattractive.'

"And it doesn't always come across in a picture, but you can be really beautiful in a still frame, and then, in life, moving around, you're ugly."

The 22-year-old actress describes herself as particularly "intense", but admits her fun side does occasionally surface too.

Kristen - who is dating her 'Twilight Saga' co-star - told The Guardian newspaper: "Yeah, I'm still a very intense person.

"I'm chilled out about some things. I'm cool. But definitely, I take things far too seriously. I am just a serious person. I love joking around, and it's obviously about mood, because sometimes I can definitely be a silly idiot.

"But most of the time I am like [private]. And I'm overtly aware of f***ing everything [up]." - Bang Showbiz