Lisa Stelly and Jack Osbourne welcome daughter Pearl

If you remember watching "The Osbournes" on MTV, it's probably a little disconcerting to think of Jack Osbourne, Sharon and Ozzy's son, as a father -- but he's all grown up now! Jack and his girlfriend, Lisa Stelly, welcomed their first child, a daughter named Pearl.

Hello! confirms that Pearl was born healthy at 8 lbs, 6 oz.

Lisa, an LA-based aspiring actress, has been engaged to Jack since September. Friends told Us that he is "a great influence on her. It's just no drama. More stable." Jack kicked an addiction to prescription painkillers and is currently directing and developing video projects.