Swift joined Kelce's family on the field at Allegiant Stadium after the Chiefs defeated the San Francisco 49ers 25-22 in an overtime victory to win their second consecutive Super Bowl title.
"I cannot believe that. I can't believe you. How did you do that?" Swift said to Kelce, who was mic'd up during the game for "Inside the NFL."
"Thank you for coming, baby. Thank you for the support. Thank you for coming," Kelce said to Swift. "Thank you for making it all the way across the world. You are the best, baby. The absolute best."
Kelce then asked his Grammy-winning girlfriend, "Was it electric?" to which Swift replied, "It was unbelievable."
In addition to the Kelce family, Swift was also seen at the game in Las Vegas with her parents, Scott and Andrea Swift, and friends including Blake Lively and Ice Spice.
The women erupted in cheers when Kansas City clinched their overtime victory over the 49ers with a touchdown.
During the pre-game on Sunday, the "Midnights" hitmaker turned up dressed in black and wearing a Chiefs letterman-style jacket while hanging out in a suite with friends and family.
Swift’s attendance at the big game showed her continued support for Kelce, whom she's been dating since last year.
With Tokyo 17 hours ahead of Las Vegas, where the Super Bowl was being held, the time difference worked in Swift's favor, giving her enough time to then travel to Las Vegas and make it to the big game.
The Super Bowl marked Swift's 13th time attending a Chiefs game. She was among those who celebrated the team's 17-10 victory against the Baltimore Ravens in the AFC Championship game on Jan. 28, clinching their Super Bowl appearance.
After the game in Baltimore ended, Swift -- who was decked out in Chiefs red and a diamond friendship bracelet -- was all smiles as she was photographed on the field, greeting Kelce in a celebratory "AFC Champions, Chiefs Are All In" T-shirt, with hugs and a kiss.
Swift could be heard telling Kelce at the time, "I've never seen anything like that in my life" as they embraced.
Less than a week after the Super Bowl, Swift will be back on the road for her next Eras Tour stop, where she is set to begin a three-night residency at Melbourne Cricket Grounds in Melbourne, Australia, on Feb. 16.