"I just felt like doing a sort of a side project as a release from the kind of high expectations of Bush, and I began working on this other material," explains the British rocker, who's married to singer Gwen Stefani.
"Without really making a conscious effort, it just became the mainstay of everything, and it just seemed to feel that Bush just kind of went to, went on hiatus, went in another room or something. Then Institute became this focal point."
Institute releases its first album, "Distort Yourself," on Sept. 13. The group played clubs in the summer and Rossdale is planning a tour to promote the album as well.