AceShowbiz -

He said, she said. Not long after daddy Lionel Richie addressed her DUI sentence and pregnancy, Nicole Richie comes out with her denial on the persistent eating disorder rumors, claiming she never had one yet is taking her diet very seriously, especially after she found out she's expecting a child.

In an exclusive interview with Diane Sawyer, aired Friday August 3rd on "20/20" at 10 p.m. EDT, the used-to-be tiny socialite insisted, "No, I do not have an eating disorder. I've never had an eating disorder, ever. It's anxiety, it's stress, it's just, it's just not being careful." Meanwhile, she also apologized for not aware early on that her being skinny could send negative message to young girls. "I'm really sorry for not accepting that earlier. It just, it took me a while."

Blamed her drug problem for causing her to experience the muck-talked weight loss, Nicole said it was part of her past that she wanted to put behind as she's getting ready for the next phase of her life. Insisted she's on a much healthier course now that she's pregnant, the mom-to-be claimed she's taking her diet very seriously.

"I eat all the time, especially now. I'm constantly hungry. I'm eating at least every hour," she said. "And just like any mother, you want to take the best care of yourself, especially while you're pregnant. I'm definitely eating healthier now."

Nicole, who reportedly already gained 10 pounds, said she is willing to gain as much weight as she has to for her baby. "It's what my baby needs and to me, numbers don't mean anything. If I gain 40 pounds, if I gain 50 pounds, then that's obviously what my body needs to do. I'm totally OK with that."

On top of that, she also avoids consuming caffeine, sushi, alcohol or drugs and rules out boyfriend Joel Madden to quit smoking. "I had to quit smoking and I was a smoker, a pack and half a day. That was hard. That was a rough week," says the Good Charlotte frontman.