Sir Mick Jagger helps launch Monty Python gigs

Sir Mick Jagger and Charlie Watts of the Rolling Stones have filmed a sketch to help promote the Monty Python team's reunion shows at London's O2 Arena.

In the skit, shown to journalists on Monday and now available on YouTube, Sir Mick jokingly suggests that "we've seen it all before".

The Pythons, he suggests, are "a bunch of wrinkly old men trying to relive their youth and make a load of money".

Monty Python Live (Mostly) runs for 10 nights at the O2 from Tuesday.

Previously unreleased tickets to all the shows will be made available shortly.

"Monty Python? Are they still going? Who wants to see that again?" Sir Mick asks as Watts sits silently beside him.

The 70-year-old singer goes on to dictate a Rolling Stones set list to an assistant, full of the rock band's well-known standards.

The five surviving members of the British comedy troupe - John Cleese, Terry Gilliam, Eric Idle, Terry Jones and Michael Palin - appeared in central London earlier to reveal details about their upcoming shows.

They include the news that astrophysicists Stephen Hawking and Brian Cox will feature in filmed skits and that comedian David Walliams will conduct red carpet interviews on 20 July, the final concert date.

Idle said Hawking is "a big Python fan so he was asked if he would" take part.

The final night, he continued, would be "like the Last Night of the Proms" and "a crazy party". The performance will be broadcast live on comedy channel Gold and in cinemas in more than 100 countries.

According to Cleese, the show - which includes recreations of the Pythons' most famous sketches as well as elaborate song and dance numbers - cost £4.5 million to produce.

"It's much more complicated and spectacular than I realised when we sat down for the read-through," said the 74-year-old, calling the concert "somewhere between a theatrical show and a rock show".

"It doesn't feel anything like the original show," said film director Gilliam, who jokingly likened the production to "a pre-posthumous memorial service".

Michael Palin (centre) rehearses a scene from the show

"The opening number's quite energetic so it sets the standard," said Palin. "I'm quite worn out after the first 10 minutes."

Yet the 71-year-old author and broadcaster said the majority of the show would consist of "classics" like the Lumberjack Song or the iconic Dead Parrot sketch.

"It would be a folly to try and write better things than our best at this age," nodded Idle. "Our motto has been 'leave them wanting less'."

According to the show's promoters, the Pythons have had "two weeks of intense rehearsals". Idle, though, insisted that the time had been adequate.

"It's been hard work; we've been working afternoons and evenings," he told reporters. "But now it feels like there's nothing more to be done."

"You spend more time rehearsing the changes between scenes than the scenes themselves," said Cleese, who predicted that the audience "is going to be an absolutely huge element".

Ministry of Silly Walks

"And we don't know what that's going to be like," chipped in Palin. "That's not something you can rehearse."

Cleese will not be recreating his famous Ministry of Silly Walks sketch "because of my various operations".

Asked later to comment on Scotland's independence referendum, Cleese instead claimed he had "a five-point peace plan for Syria" before declaring that "the Scots should do exactly what they want to do".

"What, in Syria?" replied Palin, who will be seen at one point in the show wearing a lurid tiger print jacket surrounded by a bevy of scantily clad dancers.

Monty Python Live (Mostly) - One Down, Five to Go begins its 10-night run at the O2 Arena on 1 July.

Idle, Cleese, Gilliam, Palin and Jones pose for photographers outside the London Palladium