Jeremy Corbyn came out to cheers and crowds normally reserved for headline acts at Glastonbury on Saturday and couldn't help but take a shot at Donald Trump.
The Labour leader also called on Theresa May to hold another General Election and was later pictured pulling pints at the Solstice bar for delighted fans.
After being introduced by founder Michael Eavis, Corbyn made light of a poster on a wall, which he said was for the US President, "and do you know what it says? 'Build bridges not walls'."
Later, while speaking about climate change, Corbyn joked "even Donald Trump doesn't believe there's another planet" and in relation to the Paris Climate Agreement, he said that it was up to Britain to "pick up the phone and say, 'Donald, you are wrong'."
Of Labour's surge at the General Election Corbyn said the "elites got it wrong", adding that politics "is about the lives of all of us" and that the "wonderful" thing about his party's campaign was that it "brought a lot of people back into politics because they believed there was something on offer for them."
Corbyn told the crowd that Labour is "demanding something very different in our society" and touched upon the fact that thousands of people in Britain don't have a home, or sleep rough, while "surrounded by such riches".
He called for refugees to be supported, "Let's stop the denigration of refugees... they are all human beings just like all of us here today" and for "human rights, justice, peace and democracy all over the planet".
Corbyn, speaking at the Left Field tent after his Pyramid Stage speech, cited the Labour manifesto as a "turning point" in the election.
He said: "We will think through these ideas, when the next election comes and I hope it will be very, very soon. We're ready, we're up for it."
Corbyn added: "We still have a long way to go on xenophobia on homophobia on anti-semitism... what this election campaign did, I think, was unleash a lot of thought on people. We went out and talked to people, we went out to meet people and you know what, we went out and debated people."
Corbyn hinted at renewed support for his party following the election, saying: "I don't believe all the opinion polls, but every indication I've got is there's an awful lot more people coming to the same conclusion."
To cheers of "oh, Jeremy Corbyn", the Labour leader said: "I say to the Prime Minister if she has time to watch Glastonbury this afternoon, we're ready for a General Election when you are."