Robert De Niro has received an honorary Palme d'Or at the Cannes Film Festival

During a lengthy tribute to his former co-star, DiCaprio said: "Growing up in Los Angeles, every young actor I knew watched De Niro's work.

"We studied him, trying to understand how he immersed himself so completely in his characters. He created the blueprint. He wasn't just another great actor, he was the actor."

DiCaprio, 50, starred opposite De Niro in 'This Boy's Life', the 1993 coming-of-age drama film.

And the Hollywood star recalled a humorous incident involving his former co-star.

DiCaprio shared: "The audition process was a tough one. Lots of competition. None of us knew who would get the part ... at 15 or 16 years old, I did the only thing I couldn't think to stand. I screamed at him at the top of my lungs.

"The room burst into laughing. Later that day, as the story goes, Bob was getting on his plane with a producer. Art Linson asked, 'Who do you want to play the part?' And in classic De Niro fashion, he replied, 'Second kid from the last.' Luckily, that second kid was me, and that moment changed my life forever, started my entire career in the world of cinema."

What's more, DiCaprio observed that De Niro's words always carry weight - regardless of what he's talking about.

The movie star said: "That's the thing about Bob: he doesn't say much, but when he does, it matters. Whether it's for his friends, his family, fighting for democracy or supporting the art of filmmaking - he shows up."

De Niro subsequently took to the stage to receive the Palme d'Or.

The 'Goodfellas' actor used his acceptance speech to slam US President Donald Trump's recent decision to impose a 100 percent tariff on films made in foreign countries.

De Niro - who is widely recognised as one of the greatest actors of his generation - said: "You can't put a price on creativity, but apparently you can put a tariff on it. Of course, this is unacceptable. All of these attacks are unacceptable. And this isn't just an American problem, it's a global one.

"And like a film, we can't just all sit back and watch. We have to act now. Without violence, but with great passion and determination."

De Niro also encouraged fans and people connected to the movie industry to cherish the Cannes Film Festival, describing it as a "glorious" event.

He said: "Tonight, and for the next 11 days, we show our strength and commitment by celebrating art in this glorious festival."