fun. guitarist Jack Antonoff has started his own side band called Bleachers, and he revealed its first single on Tuesday (18Feb14).

The Grammy-winning rocker wrapped fun.'s world tour last October (13), but he's not slowing down during their hiatus, focusing on a brand new group.

Antonoff took to Twitter.com on Tuesday (18Feb14) to announce the new band and release its first single, called I Wanna Get Better, on which he wrote, co-produced and sang lead vocals.

After the outpouring of support from fans, he wrote a heartfelt 'thank you' letter to his supporters on his Tumblr.com blog, divulging more information about a project he managed to create during the fun. tour and keep under wraps for a year.

He writes, "Didn't realize today would be as emotional as it is. I've been working on bleachers for a year and a half now. I didn't mean for it to be this big secret, but I didn't want anything to speak for it besides the music itself. we live in a real "big announcement next week!" type of culture, and this all meant too much to me to put anything out there besides actual music.

"But now you know, and it means the world to me. everything I do, whether it's fun., bleachers or something else, the work only comes to life because you all inspire me to make it real. I could so easily sit in the studio (or rather in bed) and just work on things forever and never get to the point. moments like today, releasing new music and being able to connect you about it are why it all matters."

Bleachers' full-length studio album is due out this spring (14), and they will make their TV debut on new talk show Late Night With Seth Meyers on 26 March (14).