Today's concert in Hyde Park in front of 150,000 people is one of the better examples of time warp concerts. The Who (retired 1989) are re-forming for the premiere live performance of their rock opera Quadrophenia (composed 1973).
In one of the strongest line-ups for years they are joined by Bob Dylan and Eric Clapton, and - representing those actually born after the Who, Dylan and Clapton were last in the charts together - Alanis Morisette.
Pete Townshend and Roger Daltrey, on stage together for the first time in years, will present an ambitious all-star production of their Mod film classic Quadrophenia.
Daltrey will perform with a black eye after the veteran glam rocker Gary Glitter, playing the Godfather in the piece, got carried away and swung his microphone stand around his head, hitting Daltrey in the face.
"Roger's got a swollen lip and eye, and a doctor is looking at it now," a spokeswoman said last night. "But he's walking, talking and smiling, and the show will go on."
Glitter was in tears after the accident. "He and Roger have been friends for years, so he was pretty upset," the spokeswoman said.
The collection of ageing rockers are the central attractions in an event the like of which has never before been seen in Britain.
Organisers hope the Mastercard Masters of Music Concert for the Prince's Trust will raise pounds 500,000.
The boxer Frank Bruno, the comedian Billy Connolly, the comic actor Stephen Fry and the newsreader Trevor McDonald will be among a hugely diverse supporting cast.
The Prince of Wales will also pay a visit and meet the stars backstage.
The concert to raise money for the Prince's Trust also features a band of unemployed young people, trained at the Prince's Trust rock school for all of a week. The unknowns might have had a rougher ride at the most famous Hyde Park concert of all, the Rolling Stones in 1969, when Mick Jagger read Shelley and released butterflies while Hell's Angels beat up hecklers.
But today bonhomie is in large supply, helped by the fact that the price of tickets at the Mastercard-sponsored gig is pounds 8, the lowest at a major rock concert for some decades, though there are VIP and corporate packages from pounds 200 upwards for those who like a luxury hotel with their music.
Quadrophenia, the story of mods and rockers in the Sixties, will be performed with an all-star cast including the actor Phil Daniels. A repeat performance in Madison Square Gardens, New York, is likely.
A bill as strong as today's in front of a sell-out crowd does not really need a PR stunt. Nevertheless, hints have been dropped all week that the three surviving Beatles might join the bill. With Mick Jagger and assorted Hell's Angels as backing group, no doubt.