Mark Forstater, who worked on the classic 1975 movie, has taken legal action, claiming he is owed royalties from hit stage show Spamalot, the Holy Grail spin-off musical.
The producer has argued that for ""financial purposes"" he should be treated as ""the seventh Python"".
The case is being heard at London's High Court, and on Wednesday, Palin took to the stand to dispute Forstater's claim.
He testified, ""It may have been what he wanted, but it was never going to be accepted by the Pythons. The idea of a 'seventh Python' just doesn't happen. It was never going to be accepted.
""I don't think there was ever any suggestion this man was going to be a 'seventh Python'. 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. There were six of us. We were a tight group. We wrote our own material.""
Palin told the court any ""major decisions"" would have been taken by ""the Pythons themselves"", and added: ""I find it really bizarre that Mark should think he would have been there writing the film with us. It just wouldn't happen.""
The case continues.