Credit: Kevin Mazur/WireImage

U2 continued their eight-night residency at Madison Square Garden on Sunday with help from Lady Gaga.

She joined the band on stage to sing “Ordinary Love,” which was originally featured in the 2013 film, Mandela: Long Walk To Freedom. Gaga sung it as a duet with Bono, and rocked out behind the piano. “‘Ordinary Love,’ an extraordinary girl, Lady Gaga!” Bono said after they finished.

Gaga is just one of the many celebrity guest stars who dropped by U2’s week of New York shows. Sir Paul McCartney, Nile Rodgers, Alicia Keys, Jon Bon Jovi, The Roots and Jimmy Fallon have all joined the band on stage.

Watch a video of Gaga’s drop-in here.