Cowell has been forced to sit out the rest of the current season after breaking his back in a weekend bike accident and now the singer who owes her career to the music mogul is joining the show as a judge.

Clarkson will take over Cowell's seat alongside Howie Mandel, Heidi Klum, and Sofia Vergara on Tuesday and Wednesday as the show returns.

"My friend, Simon Cowell, is doing better now but was in an accident and won't be able to make Tuesday and Wednesday's live shows for AGT", Clarkson explained.

"But no worries America, someone far wiser, cooler, and hotter is taking his seat! The unbelievably amazing Kelly Clarkson. You're welcome in advance!" she joked.

No stranger to U.S. talent shows, after winning the first season of American Idol, Clarkson has appeared as a judge on The Voice and was recently named Outstanding Entertainment Talk Show Host at the Daytime Emmy Awards.

Meanwhile, Cowell has pulled all his commitments for the foreseeable future after undergoing a five-hour surgery on his back following a fall from an electric bicycle in the yard of his Malibu, California home on Saturday.