Surroundedby celebrity performers and characters from the North Pole, the Obama family on Thursday led a countdown and lighted the National Christmas Tree。

　　Firstlady Michelle Obama and daughters Malia and Sasha helped President Barack Obama press a button to light the tree, an annual tradition since the 1920s. "I'm technologically challenged and I might not get this right," the president joked. "Everybody has got to help me out here."

　　
　　The Obamas and the spectators counted down from five, and the red and yellow lights came alive on the 40-foot Colorado blue spruce growing onthe Ellipse, just south of the White House. "It worked," Obama shouted。

　　
　　Performers including singer Sheryl Crow, hip hop artist Common and "American Idol" winner Jordin Sparks dazzled the crowd, bundled in coats and scarves。

　　
　　"I told Sasha we're not on 'American Idol,'" the president said at onepoint. The Obama family and Vice President Joe Biden and his grandchildren watched from seats beside the stage, behind a clear protective shielding。

　　
　　The characters Santa Claus and Mrs. Claus also joined the celebration, saying it was their "date night."

　　
　　"You know what I'm talking about," Mrs. Claus told the Obamas, referring to the couple's nights out on the town together. The president later met Santa Claus on stage and briefly danced with him。

　　
　　Before the tree was lit, Obama said its story might be Christian but its lesson is universal。

　　
　　"It represents a tradition that we celebrate as a country — a tradition that has come to represent more than any one holiday or religion, but aseason of brotherhood and generosity to our fellow citizens," he said。

　　
　　He said it's important to remember those who have lost their jobs and homes in this season as well as military service members and their families who are apart during the holidays. "We will be thinking of you and praying for you during this holiday season," he said。

　　
　　Every president has presided over the tree lighting since Calvin Coolidge in1923. The current National Christmas Tree was planted on the Ellipse in 1978.