Led Zeppelin guitarist Jimmy Page has revealed the band rehearsed in secret to see whether they could play together before announcing their comeback.
Jimmy Page broke his little finger at the beginning of November
Page told the BBC the band met for practice sessions before deciding to commit to a reunion gig.
"We wanted to see how well we'd be playing together and once we played it was without doubt we wanted to do it," he said.
The band are to play an eagerly-awaited concert on 10 December in London.
The guitarist, whose broken finger has delayed the band's reunion, said it was "exhilarating" to be playing together as a band again, but was difficult to keep the rehearsals a secret.
"The hardest thing of having anything to do with Led Zeppelin is getting together and rehearsing without anybody finding out about it," he said.
The three remaining members of Led Zeppelin will play together for the first time since 1988 in December's sold-out concert, which is a tribute to Ahmet Ertegun, the late founder of Atlantic Records.
More than one million people had applied for the £125 tickets for the show, taking the band by surprise.
Jimmy Page will perform with Robert Plant and John Paul Jones
"We were pretty confident it would sell out on the first day but the demand was totally overwhelming," said Page.
"I don't think anyone expected that demand in their wildest dreams."
Page also admitted the band's previous attempts to reform had not gone to plan.
"Live Aid was pretty shambolic," he said.
"We came together and rehearsed with a drummer we'd never met before and then we were joined by Phil Collins who we'd never played with before on this great Live Aid stage.
"We went there with the spirit of it but actually was pretty shambolic."
But the guitarist refused to be drawn on reports of tensions within the group, instead paying tribute to the band's legacy.
"We've all had our solo careers but if I was to go out on a solo project I'd certainly play Led Zeppelin music because I love it and I really enjoy playing it."
"If Robert Plant is touring, he does too. There's something wrong with the picture if all of the members aren't playing together so here's the opportunity to do it," he said.
Led Zeppelin's "best of" album, Mothership, entered the album chart at number four at the weekend.