The British rock duo performed a selection of their hits on Friday ahead of headliners Arctic Monkeys.
Drummer Ben Thatcher appeared wearing a black Arctic Monkeys vest, in a nod to the Sheffield rockers, and later patrolled the stage geeing up the crowds.
After kicking off with hit songs including Out Of The Black and Come On Over, Kerr told crowds: “Thank you so much, this is f****** insane right now, oh my God what’s going on?”
Towards the end of the set, he added: “Thank you so much Glastonbury, I have to tell you never in our wildest dreams did we ever think we’d get to do shit like this.
“My mind has been melting for the past 53 minutes or however long we’ve been playing for – this is truly f****** wild, thank you so much.”
It comes after Kerr faced an online backlash over his behaviour onstage during a show at BBC Radio 1’s Big Weekend earlier this month.
The singer had called the audience “pathetic” and left with his middle fingers in the air as he departed the stage, having previously berated them for their perceived lack of enthusiasm.
“I guess I should introduce ourselves seeing as no-one actually knows who we are. We’re called Royal Blood and this is rock music. Who likes rock music? Nine people, brilliant,” he said.
The performance was from the BBC’s online coverage, but a video shared by The Rock Revival went viral on Twitter with more than 18 million views and a number of comments.
Kerr later said he had meant “no offence” by his remarks and that his sense of humour was “dry as MDF”.
“It was somewhat of a blip on my part, because it would have taken me three minutes to think ‘Maybe these people don’t know who you are’,” he said, speaking to Greg James on his Radio 1 Breakfast Show.
“But I wasn’t going through that thought process. I was very pumped backstage and I actually really enjoyed playing, I had a great time.
“The ending to me, I felt like a sort of pro wrestler. I was walking off like a sort of pantomime villain, I didn’t feel like I’d done anything morally wrong.
“I felt like a bit of a wind-up. Honestly, that’s kind of how I felt.”