Vocalist: Katy Perry - Recording Engineer: Cathy Dennis - Drums: Dr. Luke - Producer: Dr. Luke - Bass: Dr. Luke - Programmer: Dr. Luke - Guitar: Dr. Luke - Music Production: Benny Blanco - Engineer: Emily Wright - Engineer: Sam Holland - Engineer: Mike Caffrey - Drum Programming: Mike Caffrey - Recording Engineer: Mike Caffrey - Engineer: Nick Banns - Engineer: Aniela Gottwald - Engineer: Tina Kennedy - Mixer: Serban Ghenea - Assistant Mixer: Tim Roberts - Drums: Steven Wolf - Production Coordinator: Gary Silver - Re-Mixer: Norman & Attalla - Mix Engineer: John Hanes - Mastering Engineer: Brian "Big Bass" Gardner