The great mystery of who the Santa Claus was with Taylor Swift at Arrowhead Stadium for the Christmas Day game between the Las Vegas Raiders and Kansas City Chiefs has officially been resolved.

On the latest episode of the New Heightspodcast, presented by Wave Sports + Entertainment, (starts at the 91-minute mark) Chiefs tight end Travis Kelce confirmed the man in the costume was Austin Swift, Taylor's younger brother.

The NFL posted video of Swift walking into the stadium with Santa on Monday.

NFL @NFL

Santa arrived with a very special guest. ❤️🎅 <a href="">@taylorswift13</a> | <a href="">@Chiefs</a> <a href="">

There was also another video from that same day showing Taylor and Santa riding around in a golf cart together.

Swifties suspected Austin was the man in the suit because her entire family was at the game, as was Austin's girlfriend, Sydney Ness. The 31-year-old did a good job of remaining incognito throughout the game.

He didn't take off his costume, at least in front of the cameras, and was carrying a big bag over his shoulder and rang a bell.

Unfortunately for Kelce and the Chiefs, Santa didn't do much to help their struggling offense. They had two turnovers returned for touchdowns, including a pick-six from Patrick Mahomes, in a 20-14 loss to the Raiders.

Kansas City can clinch the AFC West and a playoff berth this week with a win or tie against the Cincinnati Bengals or a win or tie by the Raiders against the Indianapolis Colts.