Taylor Swift’s appearance at Kansas City Chiefs game has boosted new beau Travis Kelce’s jersey sales by nearly 400%

Taylor Swift made waves when she was spotted at Sunday’s Kansas City Chiefs game, where she cheered on rumored beau Travis Kelce—and once again proved her ability to influence American consumers.

As the pop superstar’s unexpected appearance at the game set the internet ablaze, her presence also appeared to boost Kelce’s image, with online sales of the tight end’s jersey spiking on official merchandise sites.

“On Sunday, Travis Kelce was one of the top five selling NFL players and saw a nearly 400% spike in sales throughout the Fanatics network of sites, including NFLShop.com,” a spokesperson for Fanatics, the NFL’s official e-commerce partner, told Fortune in an email on Tuesday.

Adult Kansas City Chiefs jerseys featuring Kelce's name and player number retail from $129.99 on Fanatics, with the site's most expensive version costing $184.99.

The $89.99 kids' Travis Kelce jersey was close to selling out on Fanatics on Tuesday morning.

Swift’s potential involvement with the star athlete could also spark a new wave of interest in football, according to reports, with her fans—who are known as Swifties—telling the press they’re brushing up on the sport’s rules and that they’d go to games just to catch a glimpse of their idol.

While rumors of Swift and Kelce being romantically involved have been circulating in the media and online in recent weeks, neither of the pair has confirmed that they are in a relationship.

His brother, however, told 94.1 WIP in Philadelphia last week that he thinks reports about them dating are “all 100% true.”

During Sunday’s game, the "Shake It Off" singer was seen dressed in a red and white team jacket as she sat next to Kelce’s mom to watch him face the Chicago Bears at the Arrowhead Stadium.

Swift is currently on a break from her record-smashing Eras Tour, which picks up again on Nov. 9 in Buenos Aires.

While her influence may be extending beyond music and into the realm of sports, Swift has already established herself as a figure with huge sway over consumer habits.

Not only were fans willing to spend thousands of dollars to get their hands on tickets to her highly anticipated tour this summer, but their additional spending and travel to the shows jumpstarted local economies across America.

Earlier this year, it was projected that the Eras Tour and fellow megastar musician Beyoncé’s Renaissance Tour—both of which are expected to earn more than $1 billion in revenue—could add $5.4 billion to U.S. GDP, with even the Federal Reserve taking note of the economic impact Swift has had on America this year.

This story was originally featured on Fortune.com