I am having a lot of trouble picturing this. Which Beatle is which Musketeer? There is no Porthos in the Beatles. There is no Ringo in the Musketeers.
The script was written by George MacDonald Fraser, creator of Harry Flashman.
I would watch a Flashman movie. The likelihood of there being a Flashman movie for me to watch, in the next twenty or thirty years, seems close to zero.
Aha, but there is already a Flashman movie, directed by the same Richard Lester who directed The Three Musketeers. Malcolm McDowell plays Flashy. And Oliver Reed, who played Porthos, returns in Royal Flash as Otto von Bismarck. How about that?