Obama Pokes Fun at Conan, Psy Performs at 'Christmas in Washington' Concert

President Obama took a playful jab at Conan O'Brien during the taping of the annual Christmas in Washington charity concert Sunday.

"Lets give it up for our host, the tallest elf Ive ever seen - Conan OBrien," the president said at the event, which was taped at Washington D.C.'s National Building Museum.

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In his remarks, Obama also urged those in the audience to help those less fortunate.

"Tonight is a chance to get in the Christmas spirit; to spread some joy and sing along with artists who have much better voices than we do," he joked before turning serious. "But its also a chance to make a real difference in the lives of some very brave young people being treated at Childrens National Medical Center. Many of these kids and their parents are going through tough times right now, and your support helps give them a reason to hope - not just during the holidays, but all year round."

Diana Ross, Demi Lovato, Smash star Megan Hilty and Psy performed at the event, which will air Dec. 21 on TNT.

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Psy's performance came on the heels of his apology over a decade-old protest of the Iraq War, videos of which recently surfaced on the web.

Added Obama in his remarks: "Tonight is about Conan and Diana Ross and Santa and all the other talented folks on this stage.But its also about the Americans who are spending this holiday in a hospital bed, or a shelter, or protecting our freedom on a ! battlefield far from home. Lets keep them in our prayers, and follow Christs calling to love one another as He has loved all of us."