Madonna has gone "Gangnam Style."

The 54-year-old invited Korean pop star PSY to perform his smash single during her concert at New York City's Madison Square Garden Nov. 13. After mimicking the dance's signature choreography, Madonna and PSY then danced to her 2000 hit "Music" in front of nearly 20,000 audience members.

Earlier that evening, the pop icon said she had a "surprise" in store for the audience. Madonna later told the crowd that PSY, 34, had flown "all the way from Frankfurt, Germany" just to join her on stage.

The night wasn't all fun and games, however, as Madonna also helped raise money for victims of Hurricane Sandy. While performing her 1984 classic "Like a Virgin," the singer asked fans to donate funds for relief efforts.

When Madonna did the same fundraising the night prior, she raked in an impressive $3,000. "I went down to Rockaway Beach yesterday with my children, and we saw what was going on there, we saw the destruction," the mother of four said. "It was really sad, but we also saw amazing acts of humanity. People sharing with other people, people working hard, cleaning houses, handing out food, blankets, giving love."

To get a step-by-step "Gangnam Style" dance from PSY himself, pick up the new issue of Us Weekly, on stands Friday!