Swift joined Brittany in the Mahomes’ suite to watch the Kansas City Chiefs take on the Los Angeles Chargers on Sunday

Taylor Swift and Brittany Mahomes officially have their own secret handshake!

On Sunday, Swift, 33, joined Brittany, 28, in the Mahomes’ suite at Arrowhead Stadium to support her new beau, Travis Kelce, as the Chiefs beat the Los Angeles Chargers, while Brittany cheered on her husband, Kansas City Chiefs quarterback Patrick Mahomes.

During the second quarter, both Patrick and Kelce were at the top of their game — with the two connecting for a touchdown — and Brittany and Swift celebrated by debuting a celebratory handshake, which the NFL shared in a video posted on X. The two began by slapping the fronts and backs of their hands together five times, before then grasping each other’s hands and bumping their hips together. In another version, they topped it all off with a jumping chest bump.

The new pals were spotted practicing their handshake earlier in the game in the suite in another video posted on X.

The pair were also seen dancing as Brittany held her and Patrick’s 11-month-old son Patrick “Bronze” Lavon Mahomes III on her hip. (Their daughter, 2-year-old daughter Sterling Skye, was also pictured with her mom at the game.)

Taylor Swift and Brittany Mahomes’ handshake.NFL/X

Swift and Brittany have been hanging out since the Grammy-winner began attending Chiefs games in support of Kelce on Sept. 24. The Chargers game marked the first time she sat in the Mahomes’ suite. Previously, she had been spotted in Kelce’s suite with his parents, Donna and Ed Kelce, but switched for this week’s matchup.

DAVID EULITT/GETTY

One week after Swift’s first Chiefs game, Brittany was seen having dinner with the “Anti-Hero” singer and her friends Sophie Turner and Blake Lively. A source told PEOPLE that Brittany seemed to fit right in with Swift’s famous friends.

“They dined in a private room. Everyone had a blast,” the insider said. “They all got along and were just laughing all night over drinks and delicious food.”

Taylor Swift and Brittany Mahomes at the Oct. 22 Kansas City Chiefs game.DAVID EULITT/GETTY

The next day, all four women, as well as Hugh Jackman and Ryan Reynolds, sat in the same suite as they cheered on the Chiefs to a win against the New York Jets at the MetLife Stadium in New Jersey.

Brittany and Swift appeared to solidify their friendship the following week when the former soccer player joined Swift, Donna and Ed in the Kelce suite during the Chiefs vs. Denver Broncos game on Oct. 13.

Their friendship comes as Swift is becoming a regular at Chiefs games amid her blossoming romance with Kelce. While the Chargers game was the fourth matchup she’s attended overall, Swift and the Kansas City tight end have been stepping out in between games, as well.

Both she and Kelce made surprise cameos on the season premiere of Saturday Night Live on Oct. 14, before attending the show’s after-party hand-in-hand. They were spotted out together again the next day when they went to dinner at the Waverly Inn restaurant in New York City.

After their weekend in NYC, a source told PEOPLE that Swift and Kelce are giving their romance “a real try,” despite their busy schedules.