U2 have reflected on the emotion of returning to Mount Temple Comprehensive School for a surprise performance marking 50 years since the band first came together.
Adam Clayton said being back at the Dublin school brought him back to how he had felt as a teenager.
"I was reminded looking out there of just how kind of lost and kind of vulnerable I felt as a kid," he said.
"And I was really happy that 50 years later I felt a lot better."
The Edge described being back at the school five decades later as "extraordinary" and "very moving".
"I think we were good," he joked. "I think the sound was better this time, is my sense, and I was more in tune. So I was very happy.
"We gave 110% on the park, as we always do. It was great to be back."
Bono also joked about whether the current generation of Mount Temple students would like the band.
"But they can't ask for their money back," he said. "This is free."
The performance took place exactly 50 years after the musicians who would go on to form U2 first gathered at Larry Mullen Jr's family home in Artane on 25 September 1976.
Mullen had put a handwritten notice on a board at Mount Temple looking for musicians to form a band.
Asked if he remembered writing it, the drummer said he remembered the moment and the future members of U2 turning up at his home.
Watch: U2 sing One with young musicians from Music Generation at Mount Temple Comprehensive School
"The biggest surprise was these guys showing up, and that we are still here," he said.
Mullen said it had been "so amazing" to perform for the current generation of Mount Temple students.
"There was an understanding between the band and the audience, or the students, that we shared something that they didn't really understand, but we felt we did," he said.
"They were part of something that is such a big part of who we are. So it was absolutely so much fun. Really enjoyed it."
He then joked: "I'd like to announce we're going to do a residency here every Thursday night."
Reflecting on their roots during the return to their former school, the band also said: "We are so proud to be Irish."
Bono spoke about another former Mount Temple pupil, the late Irish writer Christopher Nolan, whose memoir was titled Under the Eye of the Clock.
He said he had been reading Nolan's work while U2 were soundchecking at the school the previous night, describing his story as "much more extraordinary" than the band's.
"He was an amazing writer," Bono said.
Standing beneath the school's clock, he added: "Now we're under the eye of the very clock he wrote about."
Bono also reflected on the influence of the school and the importance of education.
"Education is so important, and we would never have met," he said.
Music Generation musicians joined U2 for a performance of One during the gig.
Asked about the programme, Clayton said: "I think it's the thing we're most proud of, and we were very happy to have the Music Generation students with us."
He recalled how it had begun as "a small idea that grew and grew", adding: "I think now we're doing 115,000 music lessons a week."
"Music changed our lives, and for other people to have the opportunity to do that, no matter whether they can make a living out of it, is something we're very proud of," he said.
The gig also saw U2 give the first live performance of their new single Silencio.
Asked how the song had felt to play live for the first time, Bono said: "I think it sounded pretty good. I must say, stood up very well."
"A bit of punk rock. It's time to get it back to the punk spirit, I think," he added.
"So we're very proud of it. It seems to be going down well."
Silencio features on U2's forthcoming album Carnaval De Luz, which will be released on 13 November and is their first album of new material in nine years.
