apper comes out for a little “I Just Wanna Love U (Give It 2 Me) in the middle of ‘Crazy in Love.’

*Beyonce opened her Sunday concert at Madison Square Garden with her smash hit “Crazy in Love” and stunned fans when she was joined by her husband Jay-Z. [Scroll down to watch.]

The crowd went nuts as Jay-Z simply walked on stage to sing a verse from his song “I Just Wanna Love U (Give It 2 Me),” which began playing midway through “Crazy in Love.”

The husband/wife appearance marked the first time they have performed together during Beyonce’s I Am … Tour, despite Brooklyn native Jay-Z accompanying his wife to Canada and Europe over the last few months for her concerts.