Kelly Clarkson will return to 'American Idol' as a guest judge.

Kelly Clarkson

Kelly Clarkson

The singer - who won the first ever series of the reality TV show - will join the panel for the first show of the 15th and final season and will also perform.

Executive Producer Trish Kinane said: "We've invited her to be part of this season and she's really happy to be. She will be a guest judge on our first live top 10 show and she'll also perform."

Simon Cowell - who appeared on the original judging panel with Paula Abdul and Randy Jackson - is also set to return for the finale.

Trish added: "Yes, I appreciate Simon's part in the history of the show and [it's] a very important part. I think the most we can expect is for Simon to be at the finale."

Meanwhile, Jennifer Lopez, a member of the current panel alongside Harry Connick Jr and Keith Urban, insisted that the show could return in the future.

She said: "You never know with a format like this, it could work any time. It's possible. At the end of the day, you never know. This is an amazing journey to watch."

Host Ryan Seacrest added: "The network has been extremely supporting of this brand and franchise throughout the years. It's been such a blessing...the numbers look great this season, I think they we're all pleased that people are watching and some are coming back to watch that maybe didn't watch the show the last couple of years...does that mean it's the end? I'm not so sure."