The rap superstar - who is one of the co-founders of label Roc-A-Fella Records - heard the band's track 'The Club Is Alive' while hosting a World Cup party backstage at Dublin's Oxegen festival, with his crew at the weekend and was so impressed he has vowed to make the group a success in America.
An insider told the Daily Mirror newspaper: "He was heard telling pals how much he digs JLS' sound and how it reminded him of a modern day Boys II Men and Jodeci. JLS' song was playing backstage a lot over the weekend and he got excited about them.
"He knows good talent when he hears it, and is not beating around the bush on getting things kick-started with them Stateside."
Jay-Z - who has previously collaborated with the likes of Alicia Keys, Mariah Carey and wife Beyonce Knowles - is not the only high-profile star who could be helping JLS on their way to Stateside success.
The group - Aston Merrygold, Marvin Humes, Jonathan 'JB' Gill and Oritse Williams - are reportedly also enlisting the help of master magician David Blaine in the hope of incorporating illusions into their upcoming UK arena tour and future concerts.
A source revealed to the Daily Star newspaper: "These guys are chatting to David Blaine to see if he can work with them on coming up with some ideas for the production of their arena tour. They want to incorporate some illusions into their show and are keen for him to come up with the creative work on it as they're huge fans of his.
"As it's their first arena tour, JLS want to go all out and make it special for their fans."