It's hard to believe she just gave birth! Rachel Zoe looked as slim and as chic as ever while brunching at L.A.'s Bel Air Hotel on Sunday, Dec. 29 -- just one week after she and husband Rodger Berman welcomed their second son, baby boy Kaius.

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The 42-year-old fashion designer was stunning in a flowy black dress under a black blazer, with lots of chunky necklaces and a pair of oversized sunglasses. She was accompanied by son Skyler, 2, as well as newborn Kai, who was wrapped cozily in a blue blanket.

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Zoe and hubby Berman, who married in 1996, announced baby Kaius' birth on Dec. 22. "So excited to welcome our baby boy into the world...he's 7 lbs, 12 oz, beautiful, healthy, and we couldn't be happier," the celebrity stylist tweeted.

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The next day, she shared a photo of the little bundle of joy swaddled in a blanket. "I wanted you to be the first to see a picture of the beautiful new addition to our family, Kaius Jagger Berman, a.k.a. 'Kai,'" the second-time mom wrote on her website, The Zoe Report. "Rodger, Skyler and I are madly in love and will be happily hibernating for the next couple of weeks. Thank you for all of your kind words, as they mean so much to us."

This article originally appeared on Rachel Zoe Looks Slim, Chic One Week After Giving Birth to Baby Boy Kaius: Picture