The game on Sunday night between the Kansas City Chiefs and the New York Jets was not expected to be must-see TV, at least from a football perspective.

The Chiefs were the reigning Super Bowl champions and were led by the N.F.L.’s best player. The Jets were flailing after their 39-year-old would-be savior tore his Achilles’ tendon minutes into the season.

But many millions of people tuned in anyway: America’s most breathlessly covered situationship — between Kansas City’s All-Pro tight end, Travis Kelce, and pop music’s biggest star, Taylor Swift — was playing out on prime-time television.

“They are two of the biggest media entertainment entities,” said Nora Princiotti, a football writer for The Ringer who also co-hosts a popular music podcast that often focuses on Swift.

The game was surprisingly competitive, with the Chiefs narrowly beating the Jets, 23-20. And the telecast also offered a spectacular collision of the nation’s most-watched prime-time show and the ardent fans of a pop star at the height of her powers.

Maria Taylor, the host of NBC’s pregame show on Sunday night, opened her monologue with an unsubtle nod to a Swift song, “Enchanted.” Over the next hour, anchors called attention to a Swift look-alike, and cameras showed fans wearing Swift T-shirts.

The network also featured a collage of photos of Swift at last week’s Chiefs-Bears game, and around 7:42 p.m., cameras showed Swift herself at MetLife Stadium.

About 10 minutes later, NBC aired a mash-up of TikTok videos, photos and scenes from Kelce’s podcast, unspooling football story lines as well as the week’s celebrity buzz. Then the “Sunday Night Football” broadcast officially began with mentions of Jets and Chiefs players preparing to take the field.

“Oh, and yeah, she’s here: Taylor is in the house,” the play-by-play announcer Mike Tirico said while NBC showed Swift hugging someone in a luxury suite. Tirico then added, “Hi Swifties, we’ll be with you all night.”

Given Swift’s mega-fame and penchant for writing songs about her romantic relationships, her dating life has long been a subject of scrutiny. But the frenzied curiosity of the past week was rare even for Swift.

Fox Sports said the Chiefs-Bears game that Swift attended was the week’s most-watched telecast on any network, with 24.3 million viewers powered in part by a strong female audience. Fox cameras frequently panned to her reactions after Kelce, the game’s leading receiver, touched the ball.

On Sunday, NBC showed Swift several times but focused primarily on the football game. Network officials had said it was important to satisfy its regular audience, even though they knew that some viewers would be mostly interested in the 12-time Grammy winner.

“We’re aware we could be reaching new eyeballs,” Rob Hyland, the coordinating producer of “Sunday Night Football,” said on Friday.

Just before Sunday night’s game began, NBC ran yet another teaser for the contest — this one narrated by the television host Carson Daly — explaining the stakes of the football matchup with at least a half-dozen call-outs to titles of Swift songs.

When the Chiefs quickly scored a touchdown in the first quarter, the cameras turned to Swift’s celebration, even though Kelce was not involved with the play. During the commercial break that followed, NBC aired, for a second time, a high-gloss commercial for Swift’s Eras Tour concert movie that hits theaters this month.

Later in the evening, NBC showed a “Cornelia St.” sign in Manhattan (Swift wrote a song about the street); Donna Kelce, the tight end’s mother, got more screen time with Swift; and Melissa Stark gave a sideline report about the spike in Kelce jersey sales.

The Chiefs and a publicist for Swift did not respond to a request for comment.

But with Swift’s Eras Tour briefly on pause, her concert movie forthcoming and Kelce’s commitment to his football podcast as his Hall of Fame-caliber career wanes, a supercharged dose of crossover publicity on national television was probably a welcome boost, even for the already famous.

Kelce led the Chiefs with six receptions but had a quiet night by his standards. Swift gave celebratory fist bumps as the final seconds ticked off the clock.