Artist: Katy Perry - Producer: Max Martin - Producer: Ali Payami - Engineer: Sam Holland - Asst. Recording Engineer: Cory Bice - Asst. Recording Engineer: Jeremy Lertola - Editor: Peter Karlsson - Mixer: Serban Ghenea - Mix Engineer: John Hanes - Vocals: Katy Perry - Background Vocalist: Katy Perry - Background Vocalist: Sia - Background Vocalist: Max Martin - Background Vocalist: Skip Marley - Programming: Max Martin - Programming: Ali Payami - Clapping: Ali Payami - Drums: Ali Payami - Bass Guitar: Ali Payami - Synthesizer Programming: Ali Payami - Piano: Ali Payami - Percussion: Ali Payami - Percussion: Peter Karlsson - Keyboards: Max Martin - Additional Keyboards: Max Martin - Remixer: Oliver Heldens