With his marriage to Sharon Osbourne reportedly hanging by a thread, legendary rocker Ozzy Osbourne has another pressing reason to get clean and sober – his daughter Kelly’s wedding to model Matthew Mosshart, Breaking Celebrity News has exclusively learned.

“Kelly’s using a little blackmail to help her father get clean sooner rather than later. She knows he has to want it, but she thinks a little tough-love encouragement can’t hurt," a source close to the singer-turned-fashionista told Radar.

"Kelly went right for daddy’s heart – she made it clear that she needed him to be present when he walked his little girl down the aisle. Ozzy would never ruin her big day, so he promised Kelly that he would get it together way before her wedding to Matthew.”

The 28-year-old co-host of E!’s Fashion Police first met Matthew, 29, at her friend Kate Moss' wedding to The Kills guitarist Jamie Hince in July 2011.