WATCH: Lady Gaga joins U2 on stage at Madison Square Garden
U2 fans were treated to a special appearance by Lady Gaga at the band's Sunday night gig at Madison Square Garden in New York.
Gaga popped on stage, towering over Bono in her McQueen Armadillo heels, and headed to the piano to join the band for 'Ordinary Love'.
The song featured on the soundtract for the 2013 Nelson Mandela biopic Mandela: Long Walk to Freedom.
After the gig U2 posted a pic of Gaga and U2 to Instagram with the caption "All hail Her Gaganess @ladygaga #U2ieTour" and Gaga tweeted back "@U2 all hail You Too".