De Niro handpicked a then 18-year-old DiCaprio to play the lead role in 1993 drama This Boy's Life, about the relationship between a rebellious teenager and his abusive father, played by the Taxi Driver star, and he was so impressed by the young newcomer, he felt compelled to tell Scorsese all about him.
The Raging Bull director tells Parade.com, "I first heard about Leo from (De Niro). He told me in passing, 'I just did this thing called This Boy's Life with this kid named Leo DiCaprio. He's really good. You should work with him some day.' And he rarely says that. He's always really kind about other people, but he rarely says I should work with somebody.
"I saw What's Eating Gilbert Grape and I didn't realise it was him (DiCaprio) and he was terrific. And then of course Titanic. I thought he was very good in that. So when the word came around that he liked my movies, and his participation in Gangs of New York was able to get that movie made, a very special relationship started."
Scorsese will start work on his fifth collaboration with DiCaprio this summer (12), when they begin filming The Wolf Of Wall Street in New York, and he reveals their relationship works so well because they completely understand each other's vision.
He says, "We're a different generation, but he goes in the same places that I want to go. He's not afraid to go there. He's not afraid to deal with that part of himself and that's interesting. We have a different context, we grew up differently, but I think we speak the same language emotionally and psychologically. It's very lucky."