The 'X Factor' boss, 53, has signed up to take part in the sketch for Comic Relief, where he will walk down the aisle to tie the knot with a mystery bride, reported Mirror online.
"It's an industry joke that Simon will never marry, even though he has dated a string of beautiful women. So for this year's Red Nose Day, he's willing to send himself up to raise money on the night," said a source.
"All the Britain's Got Talent team will be involved, with rumours that David Walliams will declare his love for Simon in a bid to stop the marriage.
"All Simon's famous friends have Been approached, with Sinitta, Alesha Dixon, Amanda Holden, Louis Walsh and Ant 'n' Dec being asked to join in, along with a host of Simon's ex-loves.
"Loads of contestants have been invited, like Rylan Clark and the Showbears for added campness. They're going to be filming it over the next few weeks, on a day when, hopefully, everyone can make it. It's bound to be one of the highlights of the telethon," the source added.
Cowell's engagement to Mezhgan Hussainy failed to end in a trip up the aisle, and he was most recently linked to Carmen Electra.
His bride in the sketch will be revealed during the telethon screened on BBC1 on Friday March 15.