Ichiban Ippai (いちばん いっぱい Ichiban Ippai) or Full of Number Ones is a single of the band Ho-kago Tea Time, produced by Pony Canyon and published on 7 December 2011 within the album Unmei♪wa♪Endless!. The song is the opening theme song for the K-ON! Movie. The song was sung by Yui Hirasawa's voice actress Aki Toyosaki, written by Shouko Oomori, composed by Tom-H@ck and arranged by Hajime Hyakkoku.