Gwen Stefani still reigns supreme as the only girl in her growing family, and the queen of rock sure knows how to throw a party!

Stars flocked to Hotel Bel-Air in Los Angeles on Saturday to celebrate the No Doubt singer's third pregnancy with a classy blue and white bash.

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The 44-year-old looked radiant in black leather pants and a colorful blazer as she happily greeted A-list guests including Gwyneth Paltrow, Nicole Richie, Rachel Zoe, Jessica Alba, Kate Beckinsale and Chelsea Handler.

According to an insider at the event, the party lasted only a few hours and included many of the Grammy winner's non-famous friends and family as well.

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Stefani appeared "genuinely happy as she socialized with her guests," shared the insider.

The affair, which took place in the main Wolfgang Puck dining room of the hotel, was decorated with white floral arrangements, which the star tweeted a picture of.

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"Everyone seemed relaxed and cheerful in the privacy of the restaurant despite several aggressive paparazzi who we're waiting outside of the hotel," said the insider, who also observed that Gwyneth Paltrow "wanted anything chocolate" inside the event!

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As for gifts, Jessica Alba was photographed carrying in a diaper cake from her company The Honest Co., whose products are all eco-friendly. And the mom-of-two clearly hand-picked the design on the diapers for the rocker, which featured mini skulls!

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The blonde beauty also reportedly received plenty of designer baby clothes for her new addition, so we expect he'll be just as stylish as big brothers Kingston and Zuma!