Duvall, in the UK to promote his movie, Jack Reacher, with Tom Cruise, spoke with awe of meeting the late Jimmy Johnstone, the footballer affectionately known as Jinky.
At the Manchester derby yesterday, Duvall, star of The Godfather and Apocalpyse Now, was asked about his love of football.
"I am very much interested. I was in London when Pele was there, aged 16, so that dates me, and I have seen every World Cup since. I've seen a lot of the great players," he said.
"I can safely say the greatest character I have ever met, and I have met a lot, is wee Jimmy Johnstone from Scotland.
"Jinky, what a guy. I named a dog after him – a great guy, he died too young that guy. What a character, and a great player."
Duvall made a film about football, A Shot at Glory, released in 2001, which featured current Rangers manager Ally McCoist in a rare acting role.
Johnstone, who died in 2006, is best known for his time with Celtic, where he was part of the team that won the European Cup in 1967. He was voted Celtic's best-ever player by club fans in 2002.
He scored 129 goals for Celtic in 515 appearances and won 23 caps for Scotland.