Madonna fans got a big surprise last night at Madison Square Garden when Psy gave a surprise performance! That famous Gangnam Style beat was first heard as Madonna sang her 2008 hit Give It 2 Me, but the crowd went wild when Psy himself suddenly appeared and performed the entire song. Madonna and a fleet of backup dancers did their best Gangnam Style dance, and the mashup sounds pretty great, too! See for yourself: What do you think of Psy's latest mashup?