Taylor Swift kicked off the show with a world TV premiere performance of "Out of the Woods." While many were wowed by her vocals, the night's album of the year winner was not impressed. Swift, 26, was spotted wiping away tears and telling BFF Selena Gomez, "I missed that note."
Even without a single nomination this year, Adele had the best time ever. (Although she did not expect to have technical issues during her "All I Ask" production.) The British singer was spotted singing along to Swift's 1989 ballad with a beaming smile on her face.
Adele was clearly a big supporter of her peers as she was also lip-synching to The Weeknd's "Can't Feel My Face" and led a standing ovation even before he was done with his performance medley. She also met her "Hello" soulmate, Lionel Richie!
Speaking of Richie, the prolific songwriter was honored with a special musical tribute that had proud wife Chrissy Teigen singing along and swaying in her seat during husband John Legend's segment. And backstage, Wilmer Valderrama was proudly watching girlfriend Demi Lovato, who performed a soulful rendition of "Hello."
Another significant other backstage was Amber Heard, who supported husband Johnny Depp and his band, The Hollywood Vampires.
Arguably, the most outstanding performance of the night belonged to Kendrick Lamar. The rapper's powerful performance brought the star-studded audience to their feet including Rev Run, who was singing along. Even before the Compton native was finished, a majority of the crowd had given him a standing ovation.
Before Skrillex and Diplo took the stage, the Jack ü took a shot of tequila together, probably to toast their Grammy win!
And the alcohol was flowing thanks to Bruno Mars. "I'm gettin' everybody drunk!" the singer wrote along with a series of photos showing Mark Ronson, producer of the year Jeff Bhasker and song of the year winner Ed Sheeran taking a swig. He was also spotted sharing a Hash Brown with his girlfriend at McDonald's All Day Breakfast bar after the awards show.
A winner who may be toasting her big win is Meghan Trainor, who was crowned as best new artist. Shortly after hearing her name announced, Trainor's father Gary whispered in his crying daughter's ear, "You made it."
And the much-talked tribute to the late David Bowie was a big success. Lady Gaga rehearsed for over a month to get the projection mapping just right, courtesy of Intel computer programming. Good news: Intel has a two-year contract with the Grammys so expect another big performance next year as well.
And at the very end of the show, Recording Academy President Neil Portnow clarified the technical issues surrounding Adele's performance. Portnow took full responsibility telling the press room, "We had the most complicated show on television. Period. End of story. From our standpoint, we just wanted to make it clear that that was an issue on our behalf."
The party definitely didn't stop when the telecast ended. With the 2016 Grammys officially in the books, the stars let loose at several high-profile afterparties.
Swift celebrated her big night with beau Calvin Harris at the Republic Records party Hyde Sunset Kitchen & Cocktail, after arriving with squad members including Ellie Goulding, Lorde and Camila Cabello of Fifth Harmony.
"She was sitting on his lap and they were super affectionate," a source tells PEOPLE. "There was a mob of people around them."
PapJuice / WOW / INFphoto
They were joined at the party by Sir Paul McCartney – after the Beatles legend was shockingly denied entrance to Tyga's afterparty when he reportedly tried to get in alongside Beck and others.
Apparently he wasn't too upset, as the witness spotted McCartney "dancing up a storm" with wife Nancy at Republic's soiree. They were joined by Beck as the group grooved to Bowie tunes.
Other high-profile guests included The Weeknd – who got help celebrating his two wins from Bella Hadid – Kaley Cuoco and Hailee Steinfeld.
James Bay and Tony Bennett were also spotted getting chummy together.
There was also plenty to celebrate at Mark Ronson's Absolut Elyx-sponsored bash at LA's Elyx House, after the host nabbed a record of the year win for "Uptown Funk."
Big stars including Mars, Beyoncé, Jay Z, Kelly Rowland, Lady Gaga, Quincy Jones, Rashida Jones, Florence Welch, James Corden, Jon Favreau, Sam Ronson, Pamela Anderson, Absolut Elyx CEO Jonas Tahlin, and more celebrated the show by dancing the night away and sipping on signature cocktails from Absolut Elyx.
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Ronson and Favreau had the crowd on their feet as they took turns DJing the event. Welch commanded the dance floor, jumping up and down while singing along to her favorite songs. Beyoncé and Jay Z were spotted taking cute pictures of one another posing with the Elyx copper pineapples, while Gaga continued her tribute, showing up to the party with Bowie's famous lightening bolt still on her face.
Guests dined on Cap steak carne asada, Achiote grilled chicken and fajita-style veggie tacos with house-made lime crema, Heirloom tomato pico de gallo and chunky cilantro avocado whip.
Meanwhile, Missy Elliott kept things pumping at the Warner Music Group's afterparty at LA's Milk Studios, which drew the likes of Miranda Kerr and SnapChat CEO beau Evan Spiegel, Pharrell Williams, Fantasia Barrino, Garcelle Beauvais, Dwight Yoakam and Gary Clark Jr. with fianceé Nicole Trunfio.
Elliott led a spirited five-song set of her classics, including "Get Ur Freak On," and included a special shout-out to the women in the audience.
"I like to keep my shows real, so where my ladies at?" she asked. "I can't hear you!"
Kerr and Spiegel stayed close during Elliot' set, bobbing their heads to the music as Kerry kept an arm around him while sipping cocktails in the far corner of the VIP area.
Universal Music Group's afterparty also attracted a slew of coveted stars. According to WWD, Swift and Gomez made a brief appearance, arriving through a secret side entrance and staying for less than five minutes to say a quick hello to CEO Lucian Grainge.
The Weeknd and Hadid were also spotted chatting with the Universal Music Group head after making their red carpet debut at the awards show earlier in the evening.
Joe Lester / Press Line Photos / Corbis
Zendaya and NFL star Odell Beckham Jr. looked cozy while arriving together and posing arm in arm for photos.
Joe Perry also attended the afterparty following The Hollywood Vampires' debut TV performance, and the veteran musician praised bandmate Johnny Depp for his musical skills.
"It's interesting because you know he loves the acting part. He loves the art of that, but he'll tell you that music comes first," he said. "And this is a chance for him to do that and I'm glad to be able to be a part of that."
Russell Simmons also attended and told reporters he thought Kendrick Lamar and Gaga both had unbelievable performances at the show.
"We were just saying that we don't know whether it was Kendrick Lamar or Lady Gaga who had the greatest performance tonight. They were both really great," he said.
Other high-profile Universal attendees included a red-haired Joe Jonas, Brooklyn Beckham, Anna Kendrick, Ariana Grande, Mya, Camila Cabello, Lisa Vanderpump, Kacey Musgraves, Alice Cooper, James Bay, Randy Jackson and Hailee Steinfeld.
And perhaps no post-Grammys night would be complete without a little Justin Bieber. The singer celebrated his first-ever Grammys performance at a party manager Scooter Braun threw in his honor at The Nice Guy in West Hollywood.
Attracting the likes of Khloé and Kourtney Kardashian, Usher, Skrillex, Diplo and Tori Kelly, a beaming Biebs DJed and played the piano for the crowd while talking and grinning with his guests.
"Kourtney and Bieber didn't hang out much during the evening. She primarily chatted with Corey Gamble and her makeup artist until Khloé arrived and the two sisters paired off," says an onlooker.
The singer eventually came over and chatted with the duo, then continued to make the rounds with his guests," adds the onlooker.
Reporting by MELODY CHIU, NICOLE SANDS, JULIE MAZZIOTTA, RAHA LEWIS & REAGAN ALEXANDER