To be a fly on the wall when Ozzy and Sharon Osbourne first heard the news!
Ozzy's son and daughter from his first marriage each have two children, but this is the first grandchild to stem from his and Sharon's brood.
"I'm excited. I'm a little nervous," Jack said upon revealing the happy news Tuesday during a sit-down with his parents for Piers Morgan Tonight.
She missed out on this interview, but sister Kelly Osbourne is obviously rooting for Jack and his soon-to-be missus.
"Just spent the last hour on the phone with....she will be the best sister-in-law ever! <3," Stelly tweeted this afternoon.
Stelly's certainly joining a close-knit family.
"@shabooty shut your f--king mouth!" Kelly tweeted in response to a hater who had written, "What an idiot, you're not supposed to knock up your model girlfriend :P."
Looks like Jack's little one already has the fiercest aunt in town.