premise: I Kissed a Girl is only an EP.
hypothesis: `` I Kissed a Girl '' is a song recorded by American singer Katy Perry for her second studio album , One of the Boys ( 2008 ) . It was released on April 28 , 2008 , by Capitol Records as the lead single from the record . `` I Kissed a Girl '' is a pop rock song with elements of new wave . `` 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 '' .