Bynes, 27, was the star of TV's "The Amanda Show" and "What I Like About You," as well as the films "What A Girl Wants" and "Hairspray."
However, for the past year or so she has been better known for her erratic behavior, driving mishaps and Twitter rants than her acting.
In a tweet Sunday, Bynes said she had had plastic surgery, although she didn't say exactly when she had the procedure.
"I had a nose job to remove skin that was like a webbing in between my eyes," she wrote. "I wasn't going to tell anyone, but I look so much prettier in my new photos that I don't want old photos used anymore!"
She went on to say her new look was the "most amazing thing for my confidence!"