Jack Osbourne Welcomes a Baby Girl!

Sharon Osbourne's dreams of becoming a grandmother are finally a reality -- her son Jack Osbourne is now a father!

Jack, 26, and his fiancée Lisa Stelly, 25, have welcomed baby named Pearl, according to British magazine HELLO!. The little girl reportedly weighed in at 8lb. 6oz, though no other details -- including date of birth -- were announced.

The new parents became engaged back in September, after dating for just four months.

Pearl is the first child for the couple, and the first grandchild for Sharon -- Jack's dad Ozzy already has four grandchildren from the children of his first marriage.

Jack's sister Kelly took to her Twitter on Tuesday to express her joy at becoming an aunt:

thank you so much for your congratulations but they realy should be gonig to @lisamarstelly & @mrjacko! I am one proud Auntie!
— Kelly Osbourne (@MissKellyO) April 24, 2012