Usher Reunites With Ludacris & Lil Jon, Plus 26 More Things You Need to See From iHeartRadio Festival Day 2

Christopher Polk/Getty Images for iHeartMedia
Ludacris, Usher and Lil Jon perform at the 2016 iHeartRadio Music Festival at T-Mobile Arena on Sept. 24, 2016 in Las Vegas.

Fans inside Las Vegas' T-Mobile Arena on Saturday (Sept. 24) for the second and final night of the iHeartRadio Music Festival were treated to a superstar roster of artists that started with Britney Spears and wrapped up with Usher (and some of his oldest friends!) -- with some Ariana Grande, Sting and Pitbull thrown in between for good measure.

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Now that the 2016 fest is a wrap, take a look at what you might have missed from night two of #iHeartFestival:

7:48 p.m. PT: Britney Spears kicks off night 2 by getting right to work -- with her 2013 hit "Work Bitch." The pop star is clearly comfortable on a Vegas stage, with nearly three years under her belt in her Planet Hollywood residency.

8:06 p.m.: Spears surprises the crowd by bringing out G-Eazy for lead Glory single "Make Me" and the rapper's own "Me, Myself & I," reprising their sexy MTV VMAs performance from last month. G-Eazy didn't have to travel too far: He performed Friday at the Life Is Beautiful Festival in Downtown Las Vegas.

Britney Spears Brings Out G-Eazy to Close iHeartRadio Music Festival Set

8:20 p.m.: Superstar country duo Florida Georgia Line let the iHeartRadio crowd know with their first song: This is "How We Roll."

8:33 p.m.: After FGL's Tyler Hubbard and Brian Kelley reveal that their first concert and first album, respectively, were both by the Backstreet Boys, they welcome BSB themselves to perform "Everybody (Backstreet's Back)." Nick Carter even changes one of the lyrics to "As long as there'll be Vegas, we'll be coming back again."

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8:41 p.m.: The Boys are back: Backstreet re-emerges to give fans a quick preview of their upcoming Las Vegas residency with a three-song set including "I Want It That Way," "As Long as You Love Me" and "Larger Than Life" (also the name of their Planet Hollywood show).

8:53 p.m.: Following sets from Twenty One Pilots and U2 on night 1, Cage the Elephant is night 2's first rock 'n' roll rep to hit the stage, running through "Ain't No Rest for the Wicked," "Shake Me Down" and more Alternative Songs chart mainstays.

9:23 p.m.: Ariana Grande emerges in sunglasses and an oversize hooded yellow coat singing "Into You." She removes the sunglasses halfway through the song and makes full use of the big screens to show off her signature high ponytail.

9:34 p.m.: Grande performs her only non-Dangerous Woman track of the night, welcoming Zedd onstage to play drums for their collabo "Break Free."

9:55 p.m.: Zedd is back for his own set, kicking off with the Hayley Williams-featuring "Stay the Night" before launching into his biggest hit to date: the Billboard Hot 100 top 10 single "Clarity."

10:05 p.m.: Nasri from Magic! hits the stage with Zedd to sing the band's megahit "Rude" set to the producer's dance track, kicking off a string of guests. Next up is Aloe Blacc for his upbeat Zedd collab "Candyman." Then it's Hailee Steinfeld for the pair's latest single "Starving."

10:24 p.m.: "Welcome to your life/ There's no turning back." Tears for Fears hit the stage with the (newly relevant) song "Everybody Wants to Rule the World." The 1980s hitmakers didn't miss a beat, sounding great on "Head Over Heels," "Mad World" and the perfect final sing-along "Shout."

10:32 p.m.: As Tears for Fears play the lush "Sowing the Seeds of Love," we spot Pitbull's scantily clad dancers getting limber with some stretches backstage.

10:59 p.m.: Speaking of Mr. Worldwide, he finally hits the stage after a very long intro from his band (and from Phil Collins' "In the Air Tonight") to get the party started with 2012 hit "Don't Stop the Party."

11:14 p.m.: Pit pauses the party for a moment to get serious about the anti-immigrant and anti-refugee sentiment in America today. "We're all immigrants. So if we're gonna talk about the true-blooded Americans, maybe we should invite the Native Americans into this conversation," he says to wild applause.

11:27 p.m.: Sting hits the ground running with The Police's "Message in a Bottle" before playing two new songs: "I Can't Stop Thinking About You," the first single from his upcoming 57th & 9th album (due Nov. 11), and "50,000," which was inspired by the deaths of Prince and David Bowie.

11:39 p.m.: Though he did play one more hit ("Every Breath You Take"), Sting took it all the way back to 1978 with his final selection, playing The Police's "Next to You" -- the opening track from the band's debut album.

11:50 p.m.: Usher -- who earlier Saturday played the Global Citizen Festival in New York City -- miraculously materialized on the Las Vegas stage with "Crash," the first single from his just-released album Hard II Love. He almost exclusively used the set as a showcase for his new music -- also including "No Limit," sans Young Thug -- but there was one very big megahit surprise in store for fans…

12:24 a.m.: Lil Jon appeared early in the set to play DJ/hypeman for Usher, so when the track for "Lovers & Friends" started, the audience began to wonder whether the third piece of the trifecta might be in the house. He was. Ludacris came out to thunderous applause to rap his verse and handle the song's closing refrain: "Please tell your lovers and friends that Usher, Jon and Luda had to do it again."

12:29 a.m.: And they did do it again. All Usher had to do was throw a peace sign in the air and the crowd knew what was next. "Peace up, A-Town down." The Billboard Hot 100 No. 1 hit "Yeah!" took the show to the next level and helped compensate for the crowd's unfamiliarity with the rest of the set.