The Song:I haven't researched this fully yet, but in August 2016, Beck's old friend and collaborator, Cornelius, played a concert in Los Angeles commemorating his classic album,
Fantasma.
Beck went to the show (his bandmates Justin Meldal-Johnsen and Jason Falkner were also in the audience); but Cornelius had Beck up on stage to join during the final song. Beck helped Cornelius play the theremin on a song called 'Love Me Tender' -- I do not know yet if this is the famous Elvis song or a new Cornelius song (or an old Cornelius song?).