Scientist Stephen Hawking is teaming up with Monty Python for their reunion shows.
The cult comedy troupe - John Cleese, Michael Palin, Eric Idle, Terry Gilliam and Terry Jones - are kicking off their reunion gigs tomorrow (July 1).
Speaking to reporters at a central London press conference, Jones joked: "My four-and-a-half year-old daughter is coming to the last show and I dread to think what she will think of it".
Hawking will appear in the show, at London's O2, with Professor Brian Cox and a cast including a full orchestra and dozens of dancers.
Idle said: "He's a big Python fan so he was asked if he would and he said within one minute 'yes'".
Cleese said the show, which includes numerous set changes and special effects, costs around £4.5 million to stage.
He said: "It's much more complicated and spectacular than certainly I realised when we sat down for the read through for the first time".
But Idle, who has done much of the planning for the shows, said the idea was "to leave them wanting less".
Monty Python's Flying Circus was made for TV between 1969 and 1974 and generations of fans can recite lines and whole sketches.
Sixth Python Graham Chapman died of cancer in 1989 aged 48, and nine years later the five remaining members shared a stage at the Aspen Comedy Festival in the US.
The press conference, at the Palladium Theatre, began with a promotional clip for the concerts featuring Rolling Stones Mick Jagger and Charlie Watts discussing the concerts, with Jagger asking why the audience wanted to watch a "bunch of wrinkly old men trying to relive their youth".
But Idle said fans wanted to see the classic sketches which made their name, saying: "It would be odd to try and write better things than our best at this age".
Idle said he was not worried about jokes written decades ago being appreciated by a modern audience because they had not dated.
He said: "It's mainly timeless actually because we were very fortunate and followed the satire movement in England and everything was topical so when we came along we tried to knock that".
It was announced another 600 tickets would go on sale today (June 30).