Not so skinny Nicole shows off her big baby bump

She is a pin-up for size zero wannabees everywhere, but Simple Life star Nicole Richie, showed off an impressive baby bump out and about in Hollywood today.

Wearing a stretchy grey sweater and sensible flats, Nicole was accompanied by her fiancee, Good Charlotte frontman Joel Madden.

Well-wishers will be relieved to see the 26-year-old daughter of singer Lionel Richie has put on weight for her pregnancy. The troubled star had suffered a slide into drugs and driving related offences last year, which saw her spend a short time in prison.

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Nicole recently revealed her baby had saved her life. "I owe this baby everything and I have a responsibility now," she told Diane Sawyer on ABC News.

"Besides being responsible for myself, I'm now responsible for someone else. And I have to set the right examples. I have to really be someone that I would want my child to look up to."

However, the socialite admitted she could not believe she was pregnant at first. She told Access Hollywood: "I didn't believe it. I was in shock. I took about 5 different tests!"

Ms Richie and her betrothed are now eagerly awaiting their new arrival in January.

But it seems wedding bells will not be ringing any time soon. "I've got to hold something for when I get older. I can't have everything happen in one year," Nicole said.

The parents-to-be have been busy preparing for their baby and spreading some good will during the festive season.

The couple treated 200 needy children to an early Christmas with a party thrown by their newly established charity, The Richie Madden Children's Foundation.

"We really wanted to give these kids a really wonderful and special Christmas. It's our favorite holiday," said a pregnant Richie.

"It's fun for us to be with a bunch of kids who are having a good time. They make you smile," added Madden.

Nicole and Joel have decided to wait for the birth to discover the sex of 'baby Madden.'