Mary-Kate Olsen is too self-conscious to wear a bikini.The 21-year-old actress - who was treated for an eating disorder in 2004 -refuses to don swimwear on the beach as she doesn't want people commenting on how she looks.She told Entertainment Weekly magazine: "I would love to be able to swim In the ocean in Malibu. But that is asking for a bikini shot. That's inviting something that I don't want to happen. I don't need to be on a 'Who's Skinny, Who's Fat, Who's Looking Healthy, Who's Not Eating?' list."Mary-Kate - who is currently starring in hit US TV drama 'Weeds' - does her best to avoid having her photograph taken. She said: "I don't want my picture taken. The only time I think it's OK is at a red-carpet event or a photo shoot."So every time I see paparazzi, I cover my face so they don't get a picture,and I'm just 'the mean person who doesn't smile.' "Despite her dislike of the paparazzi, Mary-Kate insists she's never felt better about herself. She said: "Mentally, physically, I feel pretty on top of my game right now.Talk to me next week, I don't know. Today, I feel good."Meanwhile, Mary-Kate's twin sister, Ashley, was reportedly fuming when photographers confused her for her identical sibling at New York Fashion Week. She told paparazzi several times she was Ashley and then reportedly made her assistant find her a new seat at a fashion show because she was unhappy with her original one.