The Jonas Brothers "could release new music by end of the year." Joe Jonas says he and brothers Kevin and Nick are back in the studio and preparing new material, which could be ready for release sooner than fans think.

"I think before the end of the year definitely. We've got a couple opportunities this year concert-wise that we might do so you might hear it there!" he said.

The material will be the group's first release since 2009, and Joe said their sound has changed since their previous efforts. "I think they have more mature lyrics and as we're getting older we're able to talk about different things and we each have different inspirations. I'm really happy with the music though. I feel like it's kind of more back to what it should be, more where the roots are, meaning instruments. You know, it's not so programmed and all off a keyboard and electronic stuff, it's almost organic," he added.

Before reuniting in the studio, the brothers have been taking a break from each other, with Nick appearing in Broadway musical How to Succeed in Business Without Really Trying, while Kevin has been filming a new reality TV series Married to Jonas with his wife Danielle. Joe has kept a lower profile, but appeared as a guest judge on American Idol in 2010.