The producer of the Monty Python and the Holy Grail film is seeking higher royalties from its musical spin-off Spamalot, arguing he played a huge part in the film's creation.
Mark Forstater, who produced the 1975 cult comedy, is suing for an estimated £300,000 share of profits for the theatrical spin-off of the film, saying he should be treated as the "seventh Python".
Forstater claimed that the original screenplay was not funny until he put his own ideas into it. Much of the original film was due to be set in modern Britain featuring a character called Arthur King.
Forstater claims it was his idea to switch it to medieval times and focus on the quest of King Arthur for the Holy Grail.
At a high court hearing in London he said: "The producer of a film is essential in creating a film. If the film didn't come into existence there's not going to be any spin-offs from the film.
"The Pythons had written an initial screenplay. It was much different to the film that's been made because about half the film was King Arthur in the medieval setting and the other half was contemporary, about a man called Arthur King.
"We then discussed where they were going to take the next draft of the script.
"I gave them my input. I told them from my point of view the contemporary material was much less funny and didn't have the same resonance and I told them to expand the King Arthur [part] and that to do more medieval was more funny."
The suggestion that Forstater was a "seventh Python" was laughed off by Michael Palin, one of the original six stars of the Monty Python television series and films.
Palin told the hearing: "The idea of a seventh Python just doesn't happen. It was never going to be accepted.
"He was not the creator of the film. The film had been created by the Python team entirely.
"Mark came on board. He became the producer. But I don't think he was entitled to anything beyond that. Mark was not part of our team.
"I find it bizarre that Mark should think he would have been there writing the film with us," he added. "It just wouldn't happen."
Another member of the Python team, Eric Idle, who wrote Spamalot, found the claim "laughable". He said Forstater was "ungrateful" as he had already earned £250,000 in royalties from Spamalot.
Spamalot opened to huge critical and commercial success on Broadway in 2005.
Spamalot's enormous success has created tensions among the group after Idle dropped John Cleese as the pre-recorded voice of God in the show recently. Idle said: "It wasn't mean - he's had millions of dollars from it. He charges people a fortune for using his voice."
Cleese hit back: "I see Yoko Idle's been moaning (again) about the royalties he had to pay the other Pythons for Spamalot. Apparently, he paid me 'millions'. Actual rough figures last we checked: Yoko Idle $13m (£8m), Michael Palin $1.1m (£685,000), the others just under a million each."