My wife, Pauline, discovered this little gem in Ludwig Bemelman's fictional memoir of his time in Hollywood, Dirty Eddie (Viking, 1947). The scene is a dinner party in Malibu given in the 1930s for old and distinguished actors and actresses, including a Sir Gerald Graveline:
"But there," said the lieutenant,
with raised voice, and holding his glass in the direction of Sir
Gerald, "is the man who should play the lead, not--what's
his name?"
"Thank you. Thank you very much,
dear boy," said Sir Gerald, "but there are three
roles in the world that I do not care to play. They are, in fact,
not playable. They are: Christ, Shakespeare, and Jeeves. You start
with six strikes against you when you try to portray any of them."
Pace, Arthur Treacher and Stephen Fry.