Find out the name of Leighton Meester and Adam Brody's baby girl here! Credit: Henry S. Dziekan III/WireImage

Xoxo to this baby girl! New mom Leighton Meester and her husband, Adam Brody, have welcomed a baby girl. The gender was revealed on Thursday, Sept. 24, shortly after Us Weekly broke news that the Gossip Girl alum had given birth.

TMZ obtained the child's birth certificate, revealing that the stars named their newborn baby daughter Arlo Day.

According to the document, Meester, 29, and Brody, 35, secretly welcomed their baby girl in a hospital that wasn't the usual celeb-favored Cedars-Sinai Medical Center. The actress gave birth to the little one on Aug. 4.

Meester was last seen publicly this past July in L.A.'s Sherman Oaks neighborhood, where she beamed and cradled her big baby bump.

Us Weekly was first to reveal the news of Meester's pregnancy, as well as her hush-hush February 2014 wedding to The O.C. hunk. Click here to see the cutest photos of the couple.

The actress and her husband first met on the set of 2011's The Oranges, and again costarred together in 2014's Life Partners. During a Reddit AMA last August, Brody joked about wanting many kids with Meester.

"I say 12," he noted to a fan. "And I decide."

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