Nicole Richie weight drops to 'six stone,' on a diet of 'celery and chewing gum,' looks shockingly thin

We've been worried about her for a while.

But now Nicole Richie has stepped out looking shockingly thin after it was revealed that her weight has dropped to six stone from a diet consisting of celery, sunflower seeds and chewing gum.

The 32-year-old was infamously underweight in 2006 after shocking pictures were taken of her in a bikini on the beach.

And it seems that Nicole, who has two children with her musician husband, is now almost as thin as she was then judging by photos of her at a showbiz bash last night.

[Fashion face off: Nicole Richie v Miley Cyrus]

[Nicole Richie and Paris Hilton reunite]

The star was wearing a sleeveless black dress which highlighted her tiny arms, with her hair pulled back exposing her defined jaw.

She shared a photo of herself at the event, and fans were quick to comment with messages of concern.

One follower said: "You're setting a bad example and look much prettier with a little weight in you."

Another agreed, saying: "Oh no Nic please eat you look emaciated and drawn out in this pic."

Another fan told her: "Omg she's too skinny. I used to love her :("

Sources have suggested that Nicole is surviving on seeds, celery and juices as well as chewing gum to 'stave off hunger pangs'.

A US magazine, Star, even went as far as saying that Nicole's suffering from an eating disorder - something which a friend was quick to deny.

The friend said that Nicole is 'healthy', and went on to reveal: "This is completely false. She is not anorexic."

However, photos of Nicole in a bikini in April with a healthier figure serve to highlight her dramatic weight loss over the last few months.

A source told Star magazine that the reason for her weight loss is down to her husband, Joel Madden, being away for work in Australia.

The source explained: "Joel has always tried to keep tabs on her diet. But since he's gone so often, no one's ever really sure how much she's eating anymore. He is extremely worried about her. He tells her that she needs to focus on her health for the sake of the children, because they need their mother."

Nicole has vehemently denied suffering from an eating disorder in the past, telling Marie Claire in 2010: "I felt it was a little unfair to say someone has an eating disorder when they don't. It's extremely insulting and irresponsible. An eating disorder is serious and it's a disease."

We just hope she's happy and healthy.