Jack Osbourne

Jack Osbourne and fiancee Lisa Stelly, are new parents, having welcomed a daughter into the world. Congratulations on the arrival of their baby girl!

Her name: Pearl Osbourne arrived weighing 8 pounds and 6 ounces, according to a Hello magazine tweet that was re-tweeted by Jack and then other sites.

"Well @lisamarstelly is supposed to give birth to our baby tomorrow," the 25-year-old father tweeted last week. Guess Pearl knew how to be fashionably late!

"Still pregnant," the 26-year-old new (but exasperated) mama tweeted Friday. "Apparently I made too lovely of a home int here! #overit #comeonbaby."

But at last, she made it.

"Thank you all so much for your congratulations but they realy [sic] should be gonig to @lisamarstelly & @mrjacko! I am one proud Auntie!" added his sister Kelly Osbourne.

"Today I witnessed my first grandchild being born, life changing experience," tweeted Jack's mother, Sharon Osbourne. "She is an angel."

Ozzy Osbourne has four other grandchildren, as well. Jack got engaged to Lisa Stelly in the fall of last year. Congratulations to all!

Lisa Stelly and Jack Osbourne just got engaged.

Now it looks like they're starting a family as well!

"I'm very excited. I'm a little nervous," Jack said upon revealing the happy news that Lisa Stelly is pregnant in an interview on Piers Morgan Tonight.

She missed out on this interview, but sister Kelly Osbourne is obviously a fan of the couple. She's been taking to Twitter to silence her critics already.

Stelly's certainly joining a close-knit family.

"@shabooty shut your f--king mouth!" Kelly told one hater who wrote: "What an idiot, you're not supposed to knock up your model girlfriend :P."

The love is mutual: "Just spent the last hour on the phone with @MissKellyO ... she will be the best sister-in-law ever!

The child will be Jack's first, and the fifth grandchild for Ozzy, but the first for Sharon. Oz's son and daughter from his first marriage each have two kids.

Congratulations to the happy couple!

Jack Osbourne has a major reason to be happy today, and her name is Lisa Stelly.

Sources confirm to Us Weekly that the former reality star and the aspiring actress are engaged!

Osbourne, 25, has grown into a respected director. He was behind the camera for father Ozzy's music video for the track "Life Won't Wait" in 2010.

Jack is "a great influence on" Lisa, an insider tells the aforementioned tabloid: "It's just no drama. More stable."

[Photo: WENN.com]