YouTube and international superstar Psy, 34, performed in front of President Barack Obama and First Lady Michelle Obama at the Christmas in Washington charity concert this past Sunday, as calls for the South Korean musician to be removed from the lineup intensified.

Known for his song “Gangnam Style,” Psy came under fire for a 2004 anti-American song entitled “Dear America.” Written by N.E.X.T., a South Korean metal group, the song features Psy rapping about killing American troops and their families. Psy released a statement on Friday in which he explained that the song was “part of a deeply emotional reaction to the war in Iraq and the killing of two Korean schoolgirls that was part of the overall antiwar sentiment shared by others around the world at that time.”

He went on to say, “While I’m grateful for the freedom to express one's self, I’ve learned there are limits to what language is appropriate and I’m deeply sorry for how these lyrics could be interpreted. I will forever be sorry for any pain I have caused by those words.” Even while prepping at the concert for his performance, Psy continued to express remorse. “If it’s gonna hurt my career or not, that’s not important,” he told the Washington Post. “The most important thing is that as a human being, I really, fully regret the using of [those] kinds of words.”

White House.gov has received a petition calling for Psy not to perform. However, the petition has since been taking down for violating the site’s Terms of Participation.

Psy performed at the event along with Diana Ross, 68, Demi Lovato, 20, and Scotty McCreery, 19. Late night host Conan O’Brien, 49, also performed at the ceremony. The event is scheduled to air December 21 on TNT.

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