London (CNN) -- The five surviving Monty Python members on Thursday announced their comeback performance in London next year, and fans are eagerly anticipating which vintage sketches will be dusted off for another airing.
But their combined age of 357 years has taken its toll, and it remains to be seen how the comedians' aging bodies stand up to the often slapstick nature of Python sketches. One that John Cleese is unlikely to perform is the swivel-limbed "Ministry of Silly Walks," due to what he says are his ailing hips and knees.
Cleese says the show at the O2 Arena on July 1 will have some new material, but many old bits -- some featured in perhaps new ways -- that fans will expect, along with "comedy, pathos, music and a tiny bit of ancient sex."
"I remember going to the Royal Albert Hall and seeing Neil Diamond where he got booed in the second half for singing new numbers. People really do want to see the old hits, but we don't want to do them exactly in a predictable way, so it's going to be a mix-up, I think," Cleese adds.
Asked what he believes the modern twist will be, Terry Gilliam replies: "The fact that we can actually still walk and stand upright."
While the Python stars say they hope the new performance will appeal to a new generation of fans, they are brazen enough to admit that money was one of the main factors in their decision to reform for the first time since 1980.
"I hope it makes us a lot of money. I hope to be able to pay off my mortgage!" Terry Jones said days before Thursday's high-octane news conference at which the five Pythons announced they will perform at the O2 -- the world's biggest-grossing concert venue. Michael Palin adds that "money was part of it."
But as the five aging comedians lumber onto the stage at the Playhouse Theatre in central London, it is evident how much mutual regard they still have, despite often-fractious years working together and three decades apart. "We may not like each other, but we make each other laugh," Cleese reflects.
The show will be the first time Cleese, Jones, Gilliam, Palin and Eric Idle have performed together since the death of Graham Chapman from cancer in 1989. His presence will be sorely missed -- by both audience and stars. "We've told him he'll be on with us," Idle says, not entirely in jest, "and if there is a God, he'll turn up." There'll be a nurse on hand just in case of emergencies, he adds quickly.
Despite the show being billed as "a final reunion" and "one down, five to go," the comedians say a world tour may follow "depending on how long Eric and Mike live for," Cleese jokes. When the pair protest, saying they believe the deaths could occur in alphabetical order, he quips: "In your dreams Gilliam."
The longevity of Python -- and excitement the reunion has stirred up among fans appears to have taken the five Pythons by surprise. "No one expected this to be more than a Sunday night show at the BBC," Idle says, referring to the first TV broadcast in 1969.
Forty-five episodes and five films later, the Pythons are comic legends, with their legions of fans around the world able to recite every line of their scripts word-perfect. "I'm just shocked and amazed" at the reaction to the reunion, he says, adding that he thought they'd waited "until demand had died down."
The Python shows mostly consisted of a string of barely coherent sketches, often lacking conventional punch lines and loosely tied together by Gilliam's stream of consciousness animations.
The group dressed as old ladies, as transvestite lumberjacks, performed sketches about pompous middle-class men, used catchphrases such as "And now for something completely different," and sang ditties such as "Spam, spam, spam, spam, spam, spam, spam, spam ..."
Some of the material has never been performed on stage before, and the group says fans could expect the crunching frog sketch, a version of the dead parrot sketch and the Spanish Inquisition.
Other material "they hope people will have forgotten, so it'll appear new," Idle adds.
The sketches still make them laugh, despite the passing of time, Palin says. "We had a read-through of all the material, which to me was far more anxiety-inducing than the press conference. But it's still funny. The show is going to be spectacular."
Python has appeal around the world, he believes, because "it's seen as physical but not topical - it doesn't require knowledge of British politics or way of life. It's just quite jolly!"
CNN's Max Foster, David Wilkinson and Claudia Rebaza contributed to this report.