Even though it was one of Glastonbury's worst kept secrets, no one was really ready to believe it until it actually happened.
After that, just after 8:00 BST, Dave Grohl entered the Pyramid Stage to perform a surprise set with the Foo Fighters.
Since headlining in 2017, this was the band's first appearance at the festival. It was also their first full UK performance since drummer Taylor Hawkins passed away in 2016.
Grohl joked, "You guys realized it was us the entire time, didn't you?". Seeing your faces again is pleasant. ".
The band had been billed as The ChurnUps in the festival's lead-up, and Pulp and Blur had also been speculated to be the mystery guests.
But an hour before their performance, Foo Fighters tweeted to confirm their appearance, which caused the already-packed Pyramid Stage audience to swell to even greater numbers.
All My Life, Learn to Fly, The Pretender, and Best of You were played quickly, along with snippets of Metallica's Enter Sandman, Black Sabbath's Paranoid, and the Beastie Boys' Sabotage as compensation.
Since we only have an hour, Grohl said, "We gotta make sure we fit in all the songs we can.".
It's difficult to fathom the feelings he and the other band members were feeling.
Hawkins manned the kit during the last Glastonbury performance by the Foo Fighters. Grohl's first public appearance after his untimely death the previous year took place on the Pyramid Stage during Paul McCartney's headlining set.
Even by his own standards, the singer was like a man possessed during Friday night's performance. He never gives anything less than his absolute best.
The riffs were more intense, and the screams were more intense. Within the first minute, he was drenched in perspiration.
It was energizing and moving, particularly during a slow, stripped-down rendition of "My Hero" that seemed to be an unspoken ode to Hawkins (even more so than "Everlong," which was actually dedicated to him).
The next song was Where Are You Now, a memorial to Grohl's mother Virginia, who passed away last year. Grohl then brought out his daughter Violet to perform with him.
Despite the brief performance time, the set was more joyful than somber, with extended versions of their songs that felt upbeat and relaxed.
Josh Freese, a brand-new drummer who just joined a few months ago, blends right in. His playing is more muscular than Hawkins' melodic style, and he is a skilled session drummer. However, he is less of a focal point than Hawkins, who frequently took the mic during the band's concerts.
However, "we wouldn't be here without him," Grohl remarked to the crowd.
After an all-too-short performance, which Paul McCartney and his daughter Stella watched from the Pyramid Stage's wings, they left the stage to a flurry of applause and a promise.
"We'll return if you guys do, too. Hello again next year. ".
The UK rock duo Royal Blood will come after the group on the bill, and Arctic Monkeys, whose performance was only confirmed this morning after frontman Alex Turner spent the week recovering from acute laryngitis, will headline.
The festival, which welcomed 200,000 visitors on Wednesday morning, will have its first full day of music on Friday.
Just before noon, singer-songwriter Ben Howard launched the festival's second-largest stage, known as The Other Stage.
The Brit Award winner, who only recently made a comeback to music after having two mini-strokes, was visibly moved by the audience that came to see his early-morning performance, and he ended it with a heartfelt and prolonged goodbye and thank you.
He told BBC News after leaving the stage, "It was really special out there.
"Everyone's having a great time early on, isn't there something in the air? It has magic. ".
The Master Musicians of Joujouka were the opening act on the Pyramid Stage, performing an antiquated form of trance-inducing music from the Ahl Srif mountains of Morocco.
Ahead of a main-stage lineup that also featured dancehall-influenced rapper Stefflon Don, pop singer Maisie Peters, and Scottish rock band Texas, it was a soothing, uplifting way to get people in the mood for the day.
The latter attracted a sizable audience who sang along nearly word-for-word to hits like Say What You Want, I Don't Want A Lover, and Summer Son.
Since 1999, when Sharleen Spiteri's voice developed a slight rasp that added a welcome touch of grit to their soft-focus rock ballads, the band had not performed at the festival.
The star revealed after their performance that she had received numerous inquiries regarding Texas's inclusion on the bill, often with the implied implication that they were merely there to counterbalance the male acts.
I can only say Emily Eavis is a huge supporter of female musicians," the performer remarked.
Not because she's checking a box, though. She's giving us these opportunities because she thinks we're [expletive] incredible. " .
While ADG7 gave an impromptu Korean lesson in the middle of their relentlessly danceable set on West Holts, The Lightning Seeds hosted a laid-back singalong on The Other Stage.
A joyous performance of her hit song Call Me Maybe by Carly Rae Jepsen in the middle of the afternoon on The Other Stage was a highlight. She descended the stage scaffolding and leaped into the audience.
It's a running joke that the Canadian singer receives a sword from the audience at every performance, so the star's devoted following showed up wearing pink cowboy hats and brandishing inflatable swords.
One group of spectators even formed a human pyramid, with a man in a Super Mario costume on top, hollering the lyrics to Cut To The Feeling while swinging his beret around. This served to further enhance the surreal atmosphere.
The singer said, "I don't know what to say. "This is one of those memories that will live there forever in my mind. ".
The Other Stage will host WizKid, who will bring a taste of Lagos to Pilton, in addition to the Foo Fighters. Randamp;B singer Kelis will also bring a truckload of milkshakes to West Holts.
All weekend long, the festival will feature performances by Blondie, Guns N' Roses, Lizzo, Lana Del Rey, Loyle Carner, and Elton John.
