Featuring scantily clad dancers, a dead parrot and astrophysicist Stephen Hawking, cult British comedy troupe Monty Python promised Monday that their long-awaited reunion shows in London would be spectacular -- and of course, very silly.

The five surviving members of the group -- John Cleese, Michael Palin, Terry Gilliam, Eric Idle and Terry Jones -- open a 10-night residency at the O2 stadium on Tuesday, their first live performances together since 1980.

Costing £4.5 million ($7.7 million, 5.6 million euros), the show is a mix of sketches, singing and dancing, no mean undertaking for a group of men in their 70s.

"I'm quite worn out even after the first number," Palin, 71, told reporters ahead of the opening night.

The Pythons' unique brand of physical comedy and brilliantly absurd skits, shown on television in the 1970s and in the hit films "Life of Brian" and "Holy Grail", earned them a legion of global fans.

The first night sold out in 44 seconds in November, and they swiftly organised another nine dates each with 14,000 tickets available, most of which have been sold.

After recently losing a legal battle with a former colleague, the Pythons admit they need the money, but say they are enjoying working together again -- even if they are still bickering.

Gilliam, 73 and now a top filmmaker, said in a recent interview that he found it "depressing" that they were reforming after almost four decades spent building successful independent careers.

Idle, a 71-year-old writer and director, retorted that he was "a little arsehole" while Cleese, 74, who played Q in several Bond films, remarked drily that "Terry finds a lot of life depressing".

The gang showed every sign of getting along on Monday, although they were a little subdued, perhaps worn out by a fortnight of intense rehearsing and the challenge ahead.

They have promised to perform most of their classic sketches, including the dead parrot and the Spanish inquisition -- "deaths will occur this time," quipped Gilliam -- while Hawking will make a cameo.

"Our motto has been 'leave them wanting less'," joked Idle, 71, who has written and directed the show. "I'm happy and proud to say it's pretty filthy," he added.

The show includes archive footage of Graham Chapman, the sixth Python who died in 1989 of cancer aged just 48, and his absence is marked by its title: "One Down, Five to Go".

The final performance on July 20 will be broadcast live to cinemas around the world, a final farewell to their fans -- and Cleese insists it will really be the last.

"It's much better to do it once really well, in England where it started, and then just leave it at that," he said.