There's a great anecdote in the film, about the first Menuhin/Grappelli appearance.

The organizer knew that Menuhin was a great admirer of Grappelli's, and approached him about doing I think a TV appearance together. Menuhin demurred, saying he was in no way prepared for such a collaboration. After some persuasion, he agreed, with trepidation, to try it.

The organizer went to Grappelli: "Oh, no way, I can't do that, not with a great violinist like Menuhin!" After much persuasion he agreed. But he kept getting cold feet.

On the day of the get-together, the organizer rousted Grappelli out of his hotel room with his violin, called a taxi, and dispatched him--with two "minders" to keep him from chickening out--to meet Menuhin.

Two great masters, each cowed by the other.

Dave Oesterreich