Cowell will quit his screen roles in both the UK and US to spend more time with his family.
The abrasive celeb was expected to host a new ITV show, Walk the Line. That show will follow a similar format to The X-Factor, with musical acts competing for a grand prize of £500,000. The twist is that at the end of each show, the two highest ranked acts have the opportunity to cash out or gamble on competing in the next round.
It has now been revealed that Walk the Line will be hosted by Gary Barlow, with Cowell acting as executive producer.
Following his electric bike accident last year, which required critical surgery on his back, Cowell is stepping off our screens to focus on his partner Lauren and son Eric.
"This is a situation where I have decided it is right for me to focus on my role as the creator and producer as we build up to the hugely exciting launch," Cowell said of his role on Walk the Line.
Cowell heaped praise on his replacement.
"Gary’s musical pedigree is second to none – and we have known each other a long time now - so I am delighted he is picking up the baton for me for the first series of Walk the Line," he said of the Take That star. "I know he will do a fantastic job."
Cowell and Barlow have previously worked together on The X Factor.
"Everyone at ITV and within Camp Cowell is massively excited about this new project," a source in the Cowell camp told The Sun. "It has all the ingredients to be a huge hit. As you can imagine, workaholic Simon has been massively involved from the word ‘go’. But given all the upheavals of the past year or so, what with lockdown and his health, he’s decided now is not the time to be front of camera."
Cowell has already recorded the next series of Britain's Got Talent, which is now expected to be the last time we'll see his distinctive personality on our screens.
"He’s just finished an exceptionally busy period filming which saw him spending an extended period of time away from home, so he also wants to devote more time to his family in the coming weeks," the source said. "Clearly Simon has nothing to prove and doesn’t seek celebrity status; even after a quieter couple of years by his standards, he still gets recognised everywhere he goes. So the last thing he needs is for all that to be ramped-up again once this show runs on primetime telly. Just as he did in 2006 for the inaugural AGT launch, Simon wants help steer the ship from behind the scenes so he can ensure the series runs to his exacting demands."
Joining Barlow on the judging panel of Walk the Line will be Maya Jama, Craig David and Mabel.
"When Simon calls it’s usually with something fairly extraordinary," Barlow said in a statement. "I’m so excited to be involved in a brand new TV show, and of course my favourite part of Walk the Line is discovering new talent."
"We are delighted that Gary has decided to join the Walk The Line family and we understand and support Simon’s decision to focus on his role as producer and creator for this debut series," an ITV statement reads.
Cowell first appeared on screens in 2001 as a judge on talent show Pop Idol. He immediately established himself as a love-him-or-hate-him personality with his famously harsh critiques of contestants. He soon crossed the Atlantic to perform the same role on American Idol. In 2004 he launched The X Factor, which drew UK viewing figures of up to 20 million at its peak. Cowell made it a hat trick of talent show success with the 2007 launch of Britain's Got Talent.