The 26-year-old new dad has taken to the pages of Hello! magazine, beaming with joy alongside his baby girl, his fiancée Lisa Stelly and, of course, the matriarch of the Osbourne family, new grandma Sharon Osbourne.
But we're not sure which is sweeter—the adorable family pose, or the heartwarming words the reality star shared about becoming a dad...
"People say when you have a kid it's like instant love, but unless you've experienced it, it's impossible to comprehend," Jack told the magazine. "The moment I saw her I felt more love than I'd ever felt for anything. It was the weirdest, most overwhelming thing."
And any initial apprehension about becoming a dad was quickly washed away.
"I think I responded with, 'That's interesting,'" he said of the moment he found he and his 26-year-old partner were expecting. "What do you say? If we'd been trying for two years, of course you'd be like 'Awesome!' But we met in May and found out in August.
"I told Lisa, 'You need to give me a week to really take this in.' I had that time to get my head around the whole situation.'"
Apparently, that was all he needed. Jack and Lisa welcomed their daughter Pearl on April 24 and the duo told the mag they plan on making it even more official by tying the knot with an intimate ceremony sometime this year.
Here's hoping being a husband has the same effect on Jack as being a father, as Sharon told Hello! that she's already seen an entirely different side to her son.
"It's incredible to see Jack holding his baby girl, walking around so confidently," she said. "He's very nurturing and he and Lisa are so good together."
Congrats again, you two!