Harry Styles wanted to be precise about this.
"We're with you for the next 23 minutes," said the One Direction singer as his band took the stage at KIIS-FM's sold-out Jingle Ball concert.
A transaction disguised as a party, the annual all-star extravaganza pulls together quick performances by pop acts eager (or at least willing) to repay the powerful Top 40 radio station that helps turn their songs into hits. And Styles, a committed deflator of show-business pomp, was informing us just how much time he and his bandmates owed.
But if the air hung thick with obligation Friday night at Staples Center -- where the bill also included the Weeknd, Selena Gomez and 5 Seconds of Summer -- that didn't mean anyone was forbidden from having a good time. Or that artists didn't tend to their own agendas even as they kissed the ring.
For One Direction, which is due to take a (likely permanent) break next year, Jingle Ball served as the final U.S. stop of a victory-lap tour the British boy band has been on since the release last month of its fifth album, "Made in the A.M."
So in addition to doling out new tunes like "Drag Me Down" and "Infinity," the group happily stoked fans' welling nostalgia by reaching back for its first hit, "What Makes You Beautiful," and the folky "Story of My Life," which Liam Payne called the song "that made our American dreams come true."
True to form, these guys weren't making a big deal out of the farewell stuff; they put across a cheerful indifference, milling around the stage as though it were a train platform, even in "History," which addresses One Direction's impending hiatus head-on.
"I can feel myself getting a little emotional," Payne allowed at one point. But then he put his arm around Louis Tomlinson, and the two had a good laugh about something. Probably their plans for January.
Gomez was appealingly blasé too in her set, which pulled mostly from "Revival," the former Disney Channel star's recent album of cool but sensual electro-pop.
"It's been such an exciting year," she told the crowd in a voice that didn't sound excited in the least, and though seen-it-all is a tough look to pull off -- especially in an environment as densely packed as Jingle Ball -- Gomez made it work.
This year has been even more exciting for the Weeknd, whose string of huge 2015 hits -- "Earned It," "Can't Feel My Face," "The Hills" -- took him from R&B's margins to the very center of mainstream pop. (His brilliantly twisted "Beauty Behind the Madness" album is a virtual lock for several Grammy nominations, which are to be announced Monday.)
Like Gomez, though, the Weeknd seemed determined Friday not to appear too impressed by his newly rarefied surroundings; if anything, he was taking pleasure in defying Jingle Ball's family-friendly vibe by singing uncensored versions of druggy, sex-drenched songs that KIIS plays only in edited form.
His edge, he was assuring us, has not been smoothed by success.
You got more of that from Tove Lo, the Swedish singer who wore a black leather jacket over a high-cut leotard -- very Bianca Jagger circa 1977 -- as she performed her hits "Talking Body" and "Habits (Stay High)," both about seeking physical satisfaction without remorse. And 5 Seconds of Summer clearly had fun cranking their guitars as the closest thing Jingle Ball had to an unruly punk band.
Between these established stars were a number of up-and-comers trying to attach a face to a catchy song, including babyfaced Charlie Puth, grinning from behind a piano as he sang his cutesy doo-wop trifle "Marvin Gaye"; Conrad Sewell, whose "Start Again" sounded like Andrea Bocelli gone EDM; and actress Hailee Steinfeld, looking for a crossover to music that she gave the audience little reason to believe in.
Fortunately, Steinfeld's debt to KIIS was small. She was with us for all of about eight minutes.