Isaac Brekken, Getty Images for Clear Channel
According to The Washington Post, other performers include Demi Lovato, Scotty McCreery, Diana Ross, "Smash"'s Megan Hilty and "The Voice"'s Chris Mann.
The special will be hosted by Conan O'Brien for the second year in a row and the POTUS and his wife, Michelle Obama, will be in attendance. The show benefits the Children's National Medical Center.
The holiday-themed show will air Dec. 21 at 8 PM ET on TNT.
PSY recently broke Justin Bieber's record for the most viewed video on YouTube of all time.
Watch PSY Joining Justin Bieber on Tour
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