Zac Brown and Carrie Underwood took to the stage for the Sinatra 100 tribute concert, honoring the late crooner for what would have been his 100th birthday.

Brown performed "The Way You Look Tonight," donning a classic suit complete with a bow tie and fedora. Fans watching the Zac Brown Band frontman sing likely couldn't help but smile because his own smile was infectious; it's clear he was enjoying his time on the stage. Press play on the video above to watch the performance.

Underwood, meanwhile, sang "Someone to Watch Over Me." The country star stunned the audience, performing while wearing an elegant dress that only added to the sophisticated feel of the song. All eyes were on Underwood as she sang behind a standing mic, in front of a blue background with sparkling white lights. Once again, she proved that she has an incredible voice, adding her own personal touch to the classic song. Her performance is available to watch below.

The Sinatra 100  show was taped on Dec. 2 and aired on Dec. 6. In addition to Brown and Underwood, the tribute concert also featured Garth Brooks and Trisha Yearwood, as well as John Legend, Alicia Keys, Adam LevineUsherCeline Dion, Lady Gaga, Harry Connick Jr. and Tony Bennett.

Watch Carrie Underwood Perform "Someone to Watch Over Me":

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