Katy Perry is on the ball at Final Four show at the Armory

Finally a bona fide music superstar worthy of the Final Four.

Gimme a K, gimme an A, gimme a T, gimme a Y. What does it spell? Pop goddess.

Katy Perry rocked a Super Bowl halftime show, holds the world record for Twitter followers (107 million) and boasts nine No. 1 hits, not to mention her singing an actual basketball song, "Swish Swish."

After two nights of B-listers with the Chainsmokers (unimaginative frat-boy EDM) and Jonas Brothers (dated boy-band pop-rock), "American Idol" judge supreme Perry closed the Final Four music series on Sunday at the Armory in Minneapolis in colorful, championship style.

Even though she hasn't been on tour since August 2018, the fun-loving and fun-creating pop 'n' roller brought a scaled-down version of the spectacle that visited St. Paul in 2017. She had her six dancers in their ever-changing costumes and some inflatable stage props (a rainbow, the planet Saturn). But most of all she had a playful, in-the-moment spirit.

"I like balls," she teased early on. "Big orange basketballs."

Yes, she was caught up in Final Four fever. No more so than when she invited two fans dressed in shark costumes (remember her Super Bowl show?) to dance with her during "California Gurls." She asked Dave from Shakopee and Colin from Eden Prairie which team they were pulling for in Monday's championship game. Of course, they disagreed, just another way they stole the show.

And Perry even admitted to their star turn, though she fired off a good line about bumping and grinding with one shark and announced, "I'll tell my fiancé it was a pillow."

Yes, the 34-year-old Californian was looser, more personable and more fun at the Armory than in an arena. She summoned her hair and makeup stylist onstage to touch her up before she performed her new electronica-lite single "365" with DJ Zedd, her opening act, being shot for Monday's NCAA broadcast.

And she felt compelled to share how she'd spent her Sunday — at "a beautiful museum and then I ate at White Castle. I like the arts and fine dining."

That kind of described Perry's 90-minute performance — a mix of pop art and cheesy thrills.

Who expected the Jonas Brothers to be part of the Final Four festivities? Who even knew the Jo Bros were back together?

Clearly, the 8,000 screaming, bouncing, boy-band fans who packed the Armory on Saturday night for the Jonas Brothers' first big show since, like, 2013.

If you're not a young women between, say, 17 and 27, you probably don't know that not only are the Jo Bros back together, but just last month they scored their first No. 1 song ever, "Sucker." They've released another new tune, with a documentary film on the way and a full-blown arena tour expected.

"How many of you are seeing us for the first time having adult beverages?" Nick Jonas asked. "Cheers! Drink responsibly." And then he sipped from his red Solo cup.

Yes, the Jonas Brothers, ages 26 to 31, are now adults: two are married (one with children) and one is engaged. The fact that the once-teen heartthrobs have matured into adulthood seemed to be part of the problem with Saturday's 75-minute crowd-pleasing, no-encore show. The music was mostly exuberant teen pop-rock, which was just fine when the three brothers were Disney Channel darlings. But Nick, as a solo act, and Joe, in the group DNCE, have moved on musically.

In fact, DNCE's dance-pop "Cake by the Ocean" made a big splash on Saturday. And Nick's solo smash, "Jealous," was a big winner, too, a slice of Princely falsetto soul, that was more mature — and sexier — than any of the Jo Bros' bubble gum hits.

The trio introduced two new tunes that suggest new directions: "Cool," a breezy stroll with a Miami Beach feel that was noteworthy only because the University of Minnesota cheerleaders and marching band joined in, and "Sucker," the closing number with an au courant dance-pop vibe à la Maroon 5.

If nothing else, this comeback show proved that boy-band pop is timeless with the crowd it first connected with.