Katy Perry sings.
`` Dark Horse '' is a song recorded by American singer Katy Perry featuring rapper Juicy J . `` Hot n Cold '' is a song by American singer Katy Perry . Katy Perry . Perry rose to fame in 2008 with the release of the singles `` I Kissed a Girl '' -- which sparked controversy for its sapphic themes -- and `` Hot n Cold '' from her second album , a pop rock record titled One of the Boys .