Rascal Flatts sang a haunting rendition of 'Mary Did You Know' at the 'CMA Country Christmas' special. In an evening filled with fun and laughter -- including an appearance by Miss Piggy -- the song added a spiritual tone to the evening

Perhaps the emotion with which the three members of Rascal Flatts sang was heightened by the family flavor of the show. Several pre-taped conversations with performers -- including Rascal Flatts' members, Faith Hill, members of Little Big Town, Lauren Alaina and Martina McBride -- also featured their family to share some  personal remembrances and traditions.

Dressed in dark colors, the trio sang 'Mary Did You Know' on a dimly lit stage with a band and large illuminated Christmas trees behind them.

As they somberly finished the song, cameras turned to families in the audience, who were clearly moved by the performance.