Casey Patridge, sister of The Hills star Audrina Patridge, gave birth to her baby, Sadie Raine on January 22. Hooray!

Their infant daughter - weighing 7 pounds, 3 ounces - is the first for Casey Patridge and her fiance, Aaron Hershman.

Audrina Patridge tells Us Weekly, "She is the most beautiful baby I have ever seen and I'm so happy to be an Auntie!"

The Hills' Audrina and Casey Patridge were raised in Yorba Linda, Calif., in Orange County. They also have another sister, named Samantha.

Casey's pregnancy has been mentioned lately as the reason Audrina Patridge has been spending much of her free time in Orange County.

The Hills gossip on the web was that Audrina and Lauren Conrad were fighting, but AP says she was only out of town a lot because of Casey.