The youngest member of the Osbourne siblings at 30, Jack confessed he'd disappointed his famous mum with his latest move - having a giant tattoo on his back.
The dad-of-two showed off the huge inking when he posted a selfie on Instagram on Saturday (19 March).
Alongside the photo of his colourful Japanese-inspired tattoo, he wrote: "Here's something that most people don't know about me... Safe to say Mum wasn't thrilled at first. #tattoos #backpiece."
Fans were quick to comment, with many of his 238,000 followers liking Jack's new body art.
One wrote: "Your tattoo is awesome thanks for sharing", while another said: "That's hot jack."
An impressed fan added: "Had no idea you had that many! I like them, just shocked cause you've kept them hidden."
Among others, the reality TV star also has a tattoo of a mermaid on his forearm in tribute to his eldest daughter Pearl Clementine, who will be four in April.
Jack's wife Lisa Stelly gave birth to their second daughter Andy Rose on 13 June 2015.
MS sufferer Jack married former model Lisa in Hawaii on 7 October 2012.
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