Speaking about their new single for Sport Relief, Williams told the Daily Record: "'Proud' is pretty much the first single off the new album but we have been writing lots of songs with different producers in America for this one.
"We've been in the studio with people like Darkchild and we've kind of gone back to new jack swing, and R'n'B on the album."
He continued: "It's very exciting. The way Darkchild produces music is so amazing. He just does it on the spot. Some people have beats prepared but he didn't have any waiting for us.
"He wanted to catch a vibe to see what we were all about and make music in the studio. We started writing at the same time."
Williams added: "Bangladesh, who is known for his hip-hop, was unbelievable. We wanted to write with new people. We've got to give the fans a great album and we try to be the best we can.
"When I'm in the studio I try and make sure my swag is on point and nobody can outswag me, ever."
JLS's new single 'Proud' - which is in aid of this year's Sport Relief - is available to download now.