The QPR footballer explained that he used to sing to group member Marvin Humes when they were young, and may have continued with him had he not followed football.
"We were the original JLS," he told The Sun. "We used to sing a lot together when we were younger and do talent competitions.
"We had a group of friends that used to go round each other's houses and sing."
Ferdinand joked that he would be interested in a duet with the group if the opportunity came up.
"I'd definitely like to think about a collaboration with them in the future," he said.
JLS's Aston Merrygold was hospitalised last week after a back flip went wrong during their '4th Dimension' tour.
> JLS 'banned from city centre hotels during tour'
Watch the video for 'Proud' by JLS below: