Kristen Stewart smiles.

Robert Pattinson's girlfriend Kristen Stewart says she refuses to take things too seriously and says it's important to laugh at yourself.

The 'Twilight Saga: Breaking Dawn Part 2' actress has had a tumultuous year after cheating on her boyfriend Robert Pattinson with married director Rupert Sanders but the 22-year-old star - who has recently reconciled with Robert -believes you can't take everything too seriously.

She told Fox 5: ''Um, yeah, I mean, if you can't laugh at yourself, there's definitely a problem.

''Best not to even approach that aspect. Just think about actually who you are, rather than, you know [what's projected on you].''

Meanwhile, Kristen's 'Twilight' co-star Kellan Lutz revealed he loved working with her on scenes where her character Bella Swan discovers her new strength after becoming a vampire, especially when they had to pretend to arm wrestle.

He told Yahoo OMG!: ''I had been very much looking forward to shooting that scene with Kristen. It's fun watching her play two characters because Bella doesn't have many strengths, she's quite clumsy.

''And seeing Kristen play new Bella is really cool, I had a lot of fun. In real life I would dominate her but in the movie world, I held back.''

© Bang Showbiz