If you saw yourself being interviewed on television - not last week, but 40 years in the past - what might your reaction be? It is a fascinating question, and one I'm sure you have asked yourself many times.
Here, then, are some celebrity responses; moments in time captured just after these celebrities saw themselves being interviewed on television 40 years before.
This, from Simon Dee, who was dead famous as an English disc jockey on pirate Radio Caroline in the 1960s: "Oh my God."
Or this, from famous 1960s fashion writer Felicity Green: "Oh my God".
Or this, from Davy Jones, of the Monkees: "I used to be a heart-throb; now I'm a coronary."
These insightful reflections on a trip to a personal past are just some of what is on offer next month on Sex, Drugs and Rock 'n' Roll: The 60s Revealed on the Documentary Channel (from June 16).
The show is just one of 15 new documentaries premiering in June, on what has turned out to be one of the more regularly interesting and entertaining of Sky's more recently introduced channels.
Other shows that look appealing next month include documentaries on the excellently depressing Manchester band Joy Division, and American punk goddess Patti Smith.
Sex, Drugs and Rock 'n' Roll sounds really interesting, and the story of its making is enjoyably bizarre.
The show was put together using lost footage from 376 interviews shot by 1960s television personality Bernard Braden, someone I have never, ever heard of.
But Braden had a plan.
He would interview the 376 celebrities on all those fascinating 1960s subjects such as movies, fashion, celebrity, and of course, sex and drugs and rock 'n' roll.
He would then revisit the interviewees three years later, and see how their lives had changed.
But then came the fateful margarine incident.
Braden fell from grace when he advertised margarine on the BBC's commercial rival, ITV, and the project was lost.
The interviews resurfaced after Braden's wife died, and UK Channel Five finished what he started.
Now, a story with such promise descends into disappointment.
The "Oh my God" responses are about as good as Sex, Drugs and Rock 'n' Roll gets.
The narration is diabolically shallow, and if the interviews on the first of the series are anything to go by, either the results were dull as dishwater, or anything of any interest at all was ruthlessly edited out.
"I would like to go back with the knowledge I have today," Cilla Black says, unoriginally.
"The Beatles definitely changed things for British music," Tom Jones says, obviously.
Simon Dee does liven things up briefly with the sort of cool chit-chat that would have made him an absolute babe-magnet in the '60s.
"It's no good playing Brubeck and Tchaikovsky, right, nobody would dig that scene.
"So you slam out the pop at them, and they groove."
Groove on, Simon.
