Little else is known about the movie at the time, but the movie version is also confirmed on the show’s official website, which can be found here: (けいおん！）
The series is about a hapless girl who joins the light music club. The only drawback? She doesn’t actually play an instrument. Yui decides to learn guitar, and makes friends while learning to rock and eat lots of treats and drink lots of tea.
Watch a preview of the new movie here: (K-on!)