Artist: Katy Perry - Featuring: B.o.B. - Drums: Dr. Luke - Keyboards: Dr. Luke - Producer: Dr. Luke - Programmer: Dr. Luke - Drums: Max Martin - Keyboards: Max Martin - Producer: Max Martin - Programmer: Max Martin - Recording Engineer: Emily Wright - Recording Engineer: Sam Holland - Asst. Recording Engineer: Tatiana Gottwald - Mix Engineer: Serban Ghenea - Mix Engineer: John Hanes - Conductor: L. Leon Pendarvis - Production Coordinator: Irene Richter - Production Coordinator: Vanessa Silberman - Production Coordinator: Megan Dennis - Assistant Mixer: Phil Seaford - Additional Vocals: B.o.B.