Kelly Osbourne is reportedly determined to get her parents' marriage back on track as she thinks her dad "won't survive" without his wife Sharon.

Black Sabbath star Ozzy and Sharon have been married for 30 years and have three children together; Kelly, Jack and Aimee.

It has been claimed the couple's often explosive relationship is currently in tatters after the rocker admitted to a renewed battle with addiction.

Reports have suggested Sharon has called time on the marriage after growing tired of Ozzy's out-of-control behaviour but a source revealed Kelly has pleaded with her mom to try and save the long-term partnership.

"Kelly is determined to help get her parents' marriage back on track and has begged her mum to give Ozzy another chance, saying he won't survive without her. With him being so fragile and with his addictions, she's terrified this could push him back to the brink," a source told British magazine Closer.

Ozzy is renowned for his hell-raising past, and has a history of drink and drug abuse.

Kelly - who has suffered with prescription drug addiction - has reportedly vowed to help her parents' situation after they supported her through rehab.

"Kelly knows what it's like to relapse and how hard it is to stay clean and sober. She fears that, if Sharon doesn't take him back, he could fall off the wagon for good," the insider continued.

"She tried to persuade them to seek marriage counselling, but Sharon has told her they are 'past that point.' Sharon has said it's easy for Ozzy to talk the talk, but 44 days sober isn't enough to prove he's off the drink and drugs for good. She wants to see he's changed once and for all."

Sharon and Ozzy have denied a divorce is on the cards.