The boyband have been in the US over the past few weeks working with producers Rodney 'Darkchild' Jerkins and Babyface on material for the follow-up to their 2011 album Jukebox.
Oritse Williams told the Daily Star: "We've been in America working with new producers and writers – new to us but not new to the scene, like Rodney Jerkins.
"We're making a lot of throwback '90s new jack swing/R&B-influenced music. We're furthering our sound in that way."
He added: "We also worked with Babyface, which was a dream come true, and a guy called Bangladesh, who has done a lot of incredible hip-hop tracks. It's always good to push boundaries. That's been exciting."
JLS will return to the UK later this month to start promoting their Sport Relief charity single 'Proud', which is due to be released on March 18.
> JLS: 'We feel guilty about fans fainting at our gigs'
Watch the music video for JLS's 'Proud' below: