The 88-year-old star, still best known for his Captain Von Trapp in the 1965 musical classic, however said the movie would never be one of his favourites.
"It's not entirely true that I loathe 'The Sound Of Music'. I think Julie Andrews, who I adore, is absolutely lovely in it. I think it is her most free and naked performance - her best.
"But when you do a film with 1,000 nuns, there's a danger it can run over into a deep abyss of mawkishness," Plummer told Metro newspaper.
"I didn't like the role. I found it boring because when I was that age, in my thirties, I had already played Hamlet, Henry V, Macbeth, everything under the sun on stage and 'The Sound Of Music' was a bit of a comedown as a role," he said.