Natalie Portman: "I'm an a**hole to work with"

Actress Natalie Portman has admitted that she is an "a**hole" to work with.

Portman, 26, has revealed her belief that she upsets most of her co-stars because she never makes an effort to befriend the cast and instead chooses to focus on her acting.

Natalie said: "I must be an a**hole when I work because I don't really make friends! I don't like to get caught up in partying scene and find it really important to have my own personal space on set."

However, Portman revealed that she did make an exception for her 'My Blueberry Nights' co-star, singer Norah Jones.

Natalie explained: "Norah is a sweetheart. It's rare that you meet people through work who you're like 'Oh my God I want to spend every minute with you!' I sincerely love her.

"She's so down-to-earth and such a lovely, genuine person."