Portia de Rossi Portia de Rossi

Portia de Rossi once only ate 300 calories a day and weighed about 82 pounds, the actress told Oprah Winfrey during an interview scheduled to air Monday.

Portia de Rossi takes Ellen DeGeneres' name

"It wasn't that I was proud of it," she said of her battle with anorexia. "But it was certainly a recognition for my self-control. I definitely had some pretty amazing willpower to get down to 82 pounds. And that's what I was holding on to. I didn't think about anything else."

The Arrested Development star, who married daytime talk show host Ellen DeGeneres in 2008, recounts the details of her eating disorder in her new book Unbearable Lightness, which hits shelves Nov. 1.