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."

Nile Rodgers has revealed he wants to record with Prince.
The Chic star will be touring with 'Purple Rain' singer this year and he is hoping to get in the studio with Prince and lay down some tracks.
Speaking at the Ivor Novello Awards in London on Thursday (22.05.14), he said: "This year I've been concentrating on my new album and I'm on tour with Prince a lot ... we always play together. I've been in the studio in close proximity to Prince and we've jammed together live but this year, after we've played together, we'll see what happens.
"I don't know about making an album (with him), although we do both work really quickly."
Nile - who was honoured with the Special International Award for his incredible career at the ceremony, a prize handed to him by his friend Johnny Marr - also revealed he is set to work with Duran Duran again.
The 61-year-old guitarist performed with the band's singer Simon Le Bon and George Clinton at the International Music Summit's Legends Dinner in Ibiza on Wednesday night (21.05.14) where he was guest of honour and on the flight to the UK afterwards Nile and Simon discussed plans for their collaboration along with producer Mark Ronson.
The 'Good Times' hitmaker - who first worked with Duran Duran in 1984 on a remix of their hit single 'The Reflex' and then on their 1986 album 'Notorious' - said: "On the plane Simon and I talked about working together and we're trying to figure out how our schedules can line-up so I can work on some of the Duran Duran stuff. I do know, according to what Simon said to me, that they're going work around my schedule which is amazing. I adore Duran Duran.
"I gave Mark Ronson his first Walkman and he started bouncing on one foot and then the other and then started becoming a producer. "Can you imagine me and Mark in the same room as Duran Duran? That's going to be cool. The love is going to be insane."

Drew Barrymore admits her friends became her family when she was growing up.
The 39-year-old actress - who is married to Will Kopelman with whom she has 20-month-old Olive and one-month-old baby Frankie - reunites with her '50 First Dates' co-star Adam Sandler in comedy 'Blended' which sees two families come together and the screen beauty insists family is about those who give you a "place in the world".
Talking to Variety.com, Barrymore said: "I appreciate that terms like 'modern family' and 'blended' have become familiar in the culture as ways to describe a pride in a family that doesn't look a certain way.
"I think that my family looks traditional from the outside, but I also know that I had kind of 'zero-point-zero' family growing up, and it was my friends that became my family and they gave me a sense of place in the world and they gave me tough love."
Barrymore believes families have "no rules" and accept you for who you are, being "supportive" and "honest".
She added: "I think there are no rules. I think of family as where you feel safe. It's where you feel supported, and it's where people are being deathly honest with you."

A Whitney Houston biopic is set for release in 2015.
Angela Basset will make her directorial debut on the movie, with the working title 'Whitney Houston', which will the follow the late star's rocky relationship with her husband Bobby Brown who she separated from in 2006 before their divorce was finalised in 2007, reports E! Online.
The Oscar-nominee is thrilled to be directing the lifetime movie and feels "responsible" for telling the late star's story following her death in in February 2013, when was aged 48, and accidentally drowned at The Beverly Hilton, with heart disease and cocaine use listed as contributing factors.
Bassett, 55, said in a statement: "I have such regard for both Whitney's and Bobby's amazing talents and accomplishments, and I feel a responsibility in the telling of their story. Their humanity and bond fascinates us all. I'm beyond excited to have this opportunity to go behind the camera and into their world."
'Whitney Houston' will be executive produced and written by Larry Sanitsky and Shem Bitterman, the team behind the 2013 biographical drama 'Betty and Correta' in which Basset starred opposite Mary J Blige.
She also starred with the late Houston in the 1995 picture 'Waiting to Exhale'.
Cast details for the film are yet to be announced.

London Grammar have been told by Coldplay to always have a rest when the strain of being in a band gets to them.
The trip-hop trio recently opened for the super-group on their US shows and the young musicians took the opportunity to pick frontman Chris Martin's brain for tips to stay sane in the music industry.
Speaking at the Ivor Novello Awards in London on Thursday (22.05.14), singer Hannah Reid said: "Coldplay really liked our album, so much that they asked us to support them in LA, which we just did, we just came back from there. That was a pretty amazing experience.
"We got a chance to hang with them a little bit, Chris told us you should respect the chemistry within your band and stressed how important that is and when you know you're getting tired take days off, which has been good advice so far."
Hannah and her bandmates Dan Rothman and Dot Major were honoured at the prestigious ceremony with the prize for Best Song Musically and Lyrically for their track 'Strong'.
The group have enjoyed critical acclaim for their debut album 'If You Wait' and praise from their pop peers.
Vocalist Hannah is in demand to work with other artists but she insists her loyalty is with her "boys" in London Grammar.
When asked if she's interested in doing some collaborations, the 24-year-old singer said: "I'm definitely not. London Grammar will always be my priority and I think that as a singer in a band you have to make that decision early on how you're going to approach that ... these two are my boys."

The refurbishment of the home of Britain's Duke and Duchess of Cambridge has been completed. Prince William and his wife Duchess Catherine's new home on the Queen's Sandringham estate is now ready for them and their 10-month-old son Prince George to ...

Bear Grylls' 'The Island' will return for a second series.
The Channel 4 show, which sees 13 men attempting to survive on a remote island with a limited supply of water and only a few weapons to hunt for food, has defied critics by receiving a renewal.
Channel 4's Liam Humphreys said: "It's a brilliant concept which has exceeded our expectations. We are delighted to be bringing back Bear's experiment.
"I can't wait to watch another group face the ultimate survival challenge."
'The Island' was criticised by some viewers who claimed producers had provided the men with more water and had let two crocodiles, one of which the men killed and ate, loose on the island.
However, Channel 4 has defended the show by reassuring viewers that they had simply ensured the tropical island had enough water, animals and vegetation to keep them alive if they could use their survival instincts.
Speaking about the shows renewal, Grylls told The Sun newspaper: "Series one is proving that it is one of the toughest survival shows on television ... I'm so excited to take the next group on this adventure in series two and see if they too have the will to go through the hardship and fight for their very survival."

Sarah Jessica Parker appreciates her own mother more since having children.
The former 'Sex and the City' star - who has three children, James, 11, and four-year-old twin daughters Marion and Tabitha, with her husband Matthew Broderick - credits her mother Barbra Forste for helping her stay grounded and keep her priorities in check.
Sarah told People magazine: "We didn't have a lot growing up, but I saw my mother, who was a mother of eight, constantly volunteering her time and energy.
"Now as a mother of only three, I'm that much more cognisant of the kind of effort she made to help make us better human beings. To just watch her was inspiring."
Despite her busy schedule, the 49-year-old actress tries to give back and works with the Turnaround: Arts to help bring art programs to struggling schools in the US.
She said: "I've seen so much energy and engagement. The students look forward to that part of their day, and it's an even more joyful place to arrive every morning.
"It's changing the way these children experience school and making a difference in their lives."

Fleetwood Mac star Christine McVie says the band are open to headlining Glastonbury in the future.
The 70-year-old singer yesterday (22.05.14) confirmed that she had rejoined the band as she accepted her Lifetime Achievement gong at the Ivor Novello Awards in London, and she later confessed that she'd be more than happy to headline the festival in Somerset, if it's founder provided her with some waterproofs.
She told the Daily Star newspaper: "If Michael Eavis provides the wellies I'll be there."
The 'Go Your Own Way' hitmakers had been one of the acts rumoured to be headlining the music event before it was announced that heavy metal band Metallica had filled the final spot.
Christine first left the group, which includes bandmates Mick Fleetwood, John McVie, Stevie Nicks and Lindsey Buckingham, 16-years ago but, after performing with them at the O2 Arena in London last September, Mick announced in January that she'd be returning.
The singer has now revealed that they are working on new material for an album and are preparing for their upcoming world tour.
Speaking at the Ivor Novellos, she said: "I would like to announce that I have re-joined Fleetwood Mac and we're in the process of writing a new album for next year.
She added to the Daily Star newspaper: "We are making new music right now. It's half done, then the world tour starts in September."

Michelle Keegan didn't understand why Tina McIntrye would fall for Peter Barlow.
The 26-year-old actress' barmaid alter-ego is going to meet a sticky end when she falls to her death after an argument with a mystery killer, as part of a storyline which has seen her become romantically involved with Weatherfield's resident alcoholic and bigamist.
However, Michelle admits she wasn't on board with the liaison at first and it took her a while to understand why Tina would have got near Peter.
She told new! magazine: "I'm going to be honest, when I first heard about the storyline I didn't quite understand why Tina would do that. She's someone with good morals and she would do that to a girl, let alone a friend like Carla.
"So I was really worried, because I thought it wouldn't make sense. Obviously you just have to go along with it, but now I'm doing it, I understand it a bit more and I put it down to the fact that she's very vulnerable and has been hurt a lot of times before."
Despite deciding to leave the show of her own accord, Michelle feels sad about her exit and couldn't help taking home a few choice items from the set to remind her of her six years on the show.
Revealing what she stole on her last day of filming, she listed: "A beer mat, my earrings and maybe a few items of clothing!"
Michelle had a blast celebrating the demise of Tina with a night out in Manchester honouring the feisty barmaid.
She added: "It was a Manchester Tina theme - a lot of people had their hair up in a bun with earrings. It was saying goodbye to Tina, really. It was the last time people were going to see her and the last time I was going to play her."

Lucy Watson's kiss with Jaime Laing was the "most awful" of her life.
The 'Made in Chelsea' star was dating her co-star in the last series of the E4 reality show and reveals the moment when they lock lips onscreen at a Bollywwood-themed party took a while to film because it just didn't work.
She said: "Kissing is quite funny.
"When I kissed Jamie at the Bollywood party that was bloody awkward. We kept kissing, it was weird and wasn't working. It was like the most awful kiss of my life. Everyone was like, 'Hey, guys, do you want to try and kiss better 'cos it's really not good.' And we both got really shy. It was weird."
Lucy and Jamie are still good friends, but she's adamant she wouldn't rekindle their romance.
She explained to BANG Showbiz: "We're still really good friends."
Asked about whether she'd consider getting back with him, she said: "No!"
Lucy has just released a new dating advice book, 'The Dating Game', and she thinks it's important people - including her friend Binky Felstead, who was cheated on by boyfriend Alex Mytton - don't reunite with unfaith partners.
Speaking at the Lipsy VIP AW14 launch, she added: "I'd advise anyone who's been cheated on not to go back with them."
Lucy's book 'The Dating Game' is out now.

Gareth Edwards will direct the first 'Star Wars' spin-off.
The 'Godzilla' director will helm the first of the standalone films, each of which will focus on an individual character from the film franchise, while 'The Book of Eli' writer Gary Whitta will pen the script.
'Star Wars' creator George Lucas' production company Lucasfilm made the announcement on StarWars.com yesterday (22.05.14), although there was no confirmation as to which character the spin-off would feature.
Edwards - whose only directing credit before 'Godzilla' was the low-budget 'Monsters' - has confessed that in addition to his love for classic monster movies, he's also a huge 'Star Wars' fan.
He said: "Ever since I saw 'Star Wars' I knew exactly what I wanted to do for the rest of my life - join the Rebel Alliance!
"I could not be more excited and honoured to go on this mission with Lucasfilm."
Disney previously announced that they intend to release a new 'Star Wars' film every year starting with next year's 'Star Wars: Episode VII', meaning the first of "at least three" planned spin-offs would be released in 2016.
'Star Wars: Episode VII', which is being directed by J.J. Abrams and stars original cast members Mark Hamill, Harrison Ford and Carrie Fisher, is currently shooting in Abu Dhabi, in the United Arab Emirates.