premise: I Kissed a Girl was recorded by cats.
hypothesis: `` I Kissed a Girl '' is a song recorded by American singer Katy Perry for her second studio album , One of the Boys ( 2008 ) . `` I Kissed a Girl '' is one of eight songs by Perry to sell over 4 million digital copies in the US , the others being `` Hot n Cold '' , `` California Gurls '' , `` Firework '' , `` E.T. '' , `` Teenage Dream '' , `` Roar '' and `` Dark Horse '' .