Jennifer Hudson, Victorious star Victoria Justice and The Band Perry will also appear on the Conan O'Brien-hosted holiday special, to air Friday, December 16 at 8pm ET/PT.
President Barack Obama and First Lady Michelle Obama are among the expected guests at the annual charity event, which celebrates its 30th anniversary this year.
> Justin Bieber films 'Santa Claus Is Comin' To Town' video - watch
Christmas In Washington, which benefits the Children's National Medical Centre, will tape at the National Building Museum in Washington DC on Sunday, December 11.
Bieber and Cee Lo are also scheduled to perform at the annual Christmas In Rockefeller Centre show on NBC, which airs November 30 at 7pm ET/PT.
Bieber is currently promoting his Christmas single 'Mistletoe', taken from the holiday album Under The Mistletoe.
Watch Justin Bieber's video for 'Mistletoe' below: