Christina-Aguilera-Lady-Gaga Published December 18, 2013 at 1000 × 667 in Lady Gaga & Christina Aguilera Perform ‘Do What U Want’ Duet on ‘The Voice’ Finale [VIDEO] THE VOICE — “Live Finale” Episode 519B — Pictured: (l-r) Christina Aguilera, Lady Gaga — (Photo by: Trae Patton/NBC)