Christopher Plummer is a gentleman, said director Mike Mills.

Mike, who directed the Sound Of Music star in Beginners, readily admits that he was slightly apprehensive when he first met the actor, who has a reputation for speaking his mind.

"I was nervous in the sense that this guy has worked with [Elia] Kazan and John Houston and done so many things. As a director, of course you're a bit intimidated. When you meet him, he doesn't suffer fools," he said.

However, Christopher - who had no hesitations about the role of Hal Fields, based on Mike's real dad, after receiving a letter from the filmmaker - was a dream to work with.

"But Christopher is a gentleman, a true old-school gentleman. He likes humour, he likes a break, he's very subversive and that is fun," he continued.

"That is good to be around. It makes the set more lively. But really, Christopher, he loved to work. He doesn't take it for granted and he's very dedicated.

"It's weird to be around this 79-year-old man who has done so much stuff and is still hungry. You get the sense when you're directing him that he still strives - 'I'll make it better, I'll make it good'. So it was quite easy, it wasn't tough at all."

Beginners, which also stars Ewan McGregor and Melanie Laurent, is in cinemas now.