A heavily pregnant Nicole Richie and her bevy of guests enjoyed a Wizard of Oz themed baby shower on Sunday but it looks as though the paparazzi fuelled event may have revealed more about the starlets pregnancy than she bargained for.

The Simple Life star, who is due to give birth to her first child in January, invited around 90 guests to the party at the exlusive Beverly Hills Hotel.

Nicole's friend and Simple Life co-star Paris Hilton hosted the bash along with Nicole's sister Sophia and the pair chose the theme because it is Nicole's favourite movie.

Paris, who was wearing a blue summer dress, gushed as she arrived: "I am so happy for her, it is really great. I can't wait for them to have the baby."

Nicole's fiancé Good Charlotte singer Joel Madden, her mother Brenda, close friends DJ Samantha Ronson and Masha Gordon and Paris' sister Nicky also attended.

The party kicked-off at midday, with Nicole looking elegant in a simple black dress and oversized sunglasses.

Although Nicole and Joel are yet to confirm the sex of their baby, the couple received mostly blue gifts, suggesting they are expecting a boy.

One guest gave the soon-to-be parents baby trainers for a boy and a Tummy T Jack maternity shirt with a picture of a boy on the front.

Nicole, Joel and her family were the last to leave the party at 4.30pm.

Last week, Paris admitted she was worried about the baby shower and wanted everything to be perfect.

She said: "I honestly don't know what you play at a shower. Maybe I'll find a book or something to get some ideas.

"It's going to be really nice, with just us girls. Just Nicole's closest girlfriends and female relatives."

The heiress also claimed that despite the blue-themed event she knew nothing when it came to the sex of the child. 

"I [didn't] know what to get her. Because most of us don't know
yet what she's having. 

"She doesn't know if she's having a boy or a girl. I thought for sure she'd want to know, but she decided to wait."