Late-night host Conan O'Brien will lead the telecast, to be taped in Washington D.C.'s National Building Museum, for the second consecutive year.
Additional performers include "Smash" star Megan Hilty, former "Voice" finalist Chris Mann and "American Idol" winner Scotty McCreery .
President Barack Obama and First Lady Michelle will attend.
This is the 14th year TNT will be broadcasting "Christmas in Washington" to benefit the Children's National Medical Center.
- News