It was a scene that could have come from a Beatles gig in the 1960s.
Teenagers lined up with "Jezza" written on their faces in red lipstick, and flags saying "We heart Corbyn" flew above the crowd of thousands who gathered rhythmically chanting "Oh Jeremy Corbyn".
The Labour leader gave a stirring and impassioned speech on the Pyramid stage at Glastonbury, preaching to his core fan base, the youth.
He managed to mobilise them to influence the election result, and now he's getting them all fired up at the festival.
He attacked Donald Trump, sexism and the greedy and defended the poor, refugees, and women's rights, insisting peace and unity must win.
The crowds lapped it up as Mr Corbyn quoted his favourite poet Shelley, shouting: "Rise like lions after slumber in unvanquishable number. Shake your chains to earth like dew. Which in sleep had fallen on you. Ye are many-they are few."
And no wonder his poetic words received a rockstar welcome: this was the perfect PR opportunity, gifted to him by Michael Eavis, as he remains buoyant off the back of his election surge in popularity.
It is an astonishing turnaround from exactly a year ago, when Mr Corbyn was forced to back out of his planned appearance here because he faced a post-Brexit coup from within the party's ranks from those desperate to oust him.
But in the space of a year, Mr Corbyn's fortunes have utterly transformed and at Glastonbury Festival he was riding high on the wave of his own comeback.
In queues for the toilets, in the campsite, even during headline performances, the refrain "Oh Jeremy Corbyn" echoed.
Glastonbury's audience has delighted in singing the Labour leader's name.
Mr Glastonbury himself, Michael Eavis, told us he was thrilled to give Mr Corbyn a platform to further celebrate his success.
"This is the man that's going to deliver on the things we've been campaigning for here," said the Glastonbury founder, now in his 80s.
"He's got the hearts and minds of millions of young people, that's a huge thing," he enthused.
Singer Billy Bragg - who introduced Mr Corbyn's second speech in the Left Field - said he was proud to see how Mr Corbyn has connected with the young crowd.
"I'll let you in on a secret: I've never met a politician who didn't want to be a rockstar, but with Jeremy he has always been a part of a movement and this feels like his time.
"The election was a watershed moment ... Young people and social media played an important part.
"In the wake of the election, people feel that the tide is flowing with them, rather than against them."
Sam Coates, deputy political editor at The Times, says Mr Corbyn is on safe ground here in the Glastonbury bubble - treading in the footsteps of Tony Benn - so it is no surprise he has received a hero's welcome.
He added: "This is a crowd that couldn't be more supportive but this isn't representative of most of the electorate.
"Most people watching at home will just see this as a giant selfie in front of the Pyramid stage.
"While it goes down a storm with some, it will only reinforce the negatives with others."
But it seems thousands of people at Glastonbury fancy a little politics with their pop this year. It's not a new notion, but a resurgence of music re-engaging with the political scene.
Grime stars Stormzy, Wiley and Kano have harnessed Mr Corbyn's political sentiment, referencing him in lyrics and music videos.
The act Mr Corbyn introduced on the Pyramid stage, rap duo Run The Jewels, also embrace his mantra, having been politically outspoken in their homeland America.
And Daniel Rachel, author of Walls Come Tumbling Down, told us he remembered the first wave of motivated artists.
"The marriage of pop and politics has not been seen for 30 or 40 years, and it's now coming back and the young vote is as important as any vote," said the music writer.
"Last night the crowds at Radiohead were singing Mr Corbyn's name. It was extraordinary.
"Imagine the crowd singing for Thatcher or Gordon Brown. These are extraordinary times."
True perhaps - no matter which way politically you lean.