About 90 guests attended Nicole Richie’s "Wizard of Oz" themed baby shower on Sunday at the Beverly Hills Hotel, People reported.

The bash was organized by celebrity party planner Mindy Weiss, hosted by Richie's mother Brenda, and thrown by her sister Sophia and friends Paris Hilton and Masha Gordon.

Paris, who admitted she was worried about organizing the shower not knowing what it involves, managed to pull it off eventually choosing the "Wizard of Oz" theme because it’s Nicole’s favorite movie.

"I am so happy for her, it is really great. I can’t wait for them to have the baby," Paris said.

While most people seemed to have purchased "boy gifts" for Nicole’s baby bash, Paris insisted that the mom-to-be has no idea whether the baby is going to be a boy or a girl.

"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," the heiress explained.

Guests included Nicole’s fiancée "Good Charlotte" singer Joel Madden, "The Hills" star Lauren Conrad, DJ Samantha Ronson and Rashida Jones.

"It's nice to be supported by your friends and family. There are people here I haven't seen in so long." Richie told her guests at the event, which also raised money for the newly-established Richie Madden Children's Foundation.

Nicole and Joel, who recently revealed he can't wait to become a father, saying: "This is the most exciting thing that has happened to me, and to us," started the foundation for mothers in need.

"Nicole and Joel has asked friends to give cribs, strollers and stuffed animals to their foundation," a friend of Nicole’s said.