Monty Python decided to reunite following a £800 000 legal bill.
The British comedy troupe - Terry Jones, 71, John Cleese, 74, Terry Gilliam, 72, Michael Palin, 70, and Eric Idle, 70 - will re-enact sketches from their TV series 'Monty Python's Flying Circus' and scenes and songs from their three films in July this year with a series of live shows at The O2 in London.
John Cleese has revealed the group decided to perform together again after they lost a royalties case to Mark Forstater, who produced their 1975 film 'Monty Python And The Holy Grail'.
Talking on British talk show 'Alan Carr's Chatty Man', John said: "We had an £800,000 bill from a legal case and the costs were enormous. We all got together and thought, 'How are we going to pay an £800,000 legal bill?' and someone said, 'Let's do a show.' "
In addition, John is in need of the extra income to pay his ex-wife Alyce Faye Eichelberger more than £600,000 a year.
He has been trying to pay Alyce nearly £8 million in money and assets over the last four years, following their divorce in 2008, and is obligated to pay her £612,000 annually until 2016.
The group - who last performed live together at the Hollywood Bowl in 1980 and were last on stage in the UK 40 years ago - would like to experiment with new material but think fans would prefer the old gags.
John added: "People want the old stuff. They know the sketches."