These are all the people who worked on ARTPOP:   Lady Gaga – production, vocals (all tracks); bass arrangement (2); guitar arrangement (4, 8, 14); synth arrangement (7); backing vocals arrangement (8, 9, 14); piano arrangement (8, 14); piano (13); executive producer Doug Aldrich – guitar (6) Sean C. Erick – horn (6) Natalie Ganther – backing vocals (5, 8, 9, 14) Nicole Ganther – backing vocals (5, 8, 9, 14) Lyon Gray – backing vocals (5, 8, 9, 14) R. Kelly – vocals (7) Jason Lader – digital ed