National Christmas Tree Lighting 2015 (30 images)

U.S. President Barack Obama sings along with daughter Malia as entertainers Trombone Shorty (L) and Reese Witherspoon join in at the conclusion of the National Christmas Tree Lighting on the Ellipse, December 3, 2015, in Washington, D.C. The lighting kicks off the Holiday Season of festivities in the nation's capital. Photo by Mike Theiler/UPI

Actress Reece Witherspoon (R) and Miss Piggy await the arrival of First Lady Michelle Obama at the National Christmas Tree Lighting on the Ellipse, attended by U.S. President Obama and the First Family, December 3, 2015, in Washington, D.C. Photo by Mike Theiler/UPI

President Barack Obama and daughters Malia and Sasha, mother-in-law Marian Robinson and first lady Michelle Obama join performers from the stage during the national Christmas tree lighting ceremony on the Ellipse south of the White House December 3, 2015 in Washington, D.C. The lighting of the tree is an annual tradition attended by the president and the first family. Pool photo by Olivier Douliery/UPI

U.S. President Barack Obama joins Santa Claus in a sing-a-long at the conclusion of the National Christmas Tree Lighting on the Ellipse, December 3, 2015, in Washington, D.C. The lighting kicks off the Holiday Season of festivities in the nation's capital. Photo by Mike Theiler/UPI