The La La Land star described meeting the Titanic actor as “the most surreal moment of my life”.
It's often been reported that Matthew turned down Leonardo DiCaprio's role, but he's insisted that's "not factual".
The Hollywood actor, who is an environmental campaigner himself, said Greta's message should be a "wake-up call to world leaders".
And how a fearless British reporter helped uncover it.
An inside look at one of 2019's best films.
Margot Robbie Joins Brad Pitt and Leonardo DiCaprio At Dazzling Once Upon A Time In Hollywood Premiere
The Quentin Tarantino film features the Charles Manson murders of 1969.
With a three-minute standing ovation at the Cannes Film Festival, Quentin Tarantino’s ninth feature film stars Leonardo DiCaprio, Brad Pitt, Margot Robbie and is set to be an all-time great.
“I will miss him everyday. Every minute. Every second.”
Stalking, death threats and numerous criminal charges: My investigation into environmental corruption quickly became the unravelling of the Malaysian government — at great personal cost
'I think we both had a specific opinion about each other...'