The 91st annual tree-lighting ceremony kicks off the holiday season with a dazzling display of musical talents, star-studded surprises, and the lighting of the Rockefeller Center Christmas tree; Emmy and Grammy Award winner Kelly Clarkson hosts.NBC News' TODAY co-anchors Savannah Guthrie, Hoda Kotb, Al Roker, and Craig Melvin co-host the highly anticipated holiday special. Before the special, an additional live hour broadcasts on various NBC channels and affiliates nationwide, starting at 7 p.m. ET and hosted by ACCESS Hollywood Host Mario Lopez and WNBC anchors Natalie Pasquarella and David Ushery.