**The crowd at New York City's Madison Square Garden on Saturday night were in for a surprise when Lady Gaga joined U2 on stage and performed a song with the legendary rock band. Lady Gaga walked on stage in her Alexander McQueen shoes to sing "Ordinary Love," a song written by Bono to honor the late Nelson Mandela and included in the biography film Mandela: Long Walk to Freedom. Watch below...** **Lady Gaga joins U2 on stage at Madison Square Garden Posted Monday at 5:46 AM FACEBOOK TWITTER GOOGLE PLUS 19 COMMENTSLady Gaga joins U2 on stage at Madison Square Garden Photo credit: Kevin Mazur/WireImage via ew.com The crowd at New York City's Madison Square Garden on Saturday night were in for a surprise when Lady Gaga joined U2 on stage and performed a song with the legendary rock band. Lady Gaga walked on stage in her Alexander McQueen shoes to sing "Ordinary Love," a song written by Bono to honor the late Nelson Mandela and included in the biography film Mandela: Long Walk to Freedom. Watch below... Monsters, what did you think of the performance? Sound off in the comments below!** #ladygaga #littlemonsters #love #mothermonster #gaga #pawsup #U2 #MadisonSqaure #news