The lads will perform Rihanna’s first number one hit Umbrella on the ITV1 show, while Alexandra Burke sings with Westlife and Eoghan teams up with Boyzone, according to The Mirror.
The live performance with an established star can make or break X Factor hopefuls.
In last year’s final, Leon Jackson stormed to victory after performing with Kylie Minogue – having started the show a 6-1 outsider.
And with JLS’s popularity soaring, bookies have cut the odds on them winning to 7-2, thinking history may repeat itself.
The boys, Oritse Williams and Jonathan Gill, both 21, Aston Merrygold, 20, and Marvin Humes, 23, would be the first group to win the X Factor.
A show insider said: “They are thrilled to be working with Rihanna. It is a massive coup. She has an incredibly wide fanbase which is bound to help pull votes. The feeling is that Rihanna’s backing is the clincher.
“Even Simon Cowell has admitted they could win. He views them as an increasingly profitable asset.”
Earlier this week, more than 30 fans were taken to hospital following a crowd scramble during a JLS gig at Fairfield Halls in Croydon, South London.
On Wednesday, ousted finalist Laura White backed JLS to win but Alexandra was still 8-13 favourite, with Eoghan 4-1.