premise: Katy Perry's song Roar (song) came out for the first time on her fifth studio album.
hypothesis: Katy Perry . She became the first artist with multiple videos to reach one billion views on Vevo with the videos for its songs `` Roar '' and `` Dark Horse '' . `` Roar '' is a song by American singer Katy Perry for her fourth studio album , Prism ( 2013 ) .