The 'Revenant' actor, Leonardo DiCaprio , who is a staunch environmental campaigner - was granted a private audience with the head of the Catholic Church last Thursday and it was an "incredible honor" for the 41-year-old star to meet with him.

Speaking backstage at the Screen Actors Guild (SAG) Awards last night, Leonardo said: "He's been inspiring and revolutionary, to come out and be outspoken about the issue of climate change and endorse the scientific community.

"We have 99% of the scientific community now saying climate change exists and it's caused by mankind. Anyone who doesn't believe in climate change doesn't believe in science. So the fact that he has come out as the spiritual leader endorsing the scientific movement is unprecedented, and it was an incredible honour to meet him."

During the meeting, the 'Wolf of Wall Street' star reportedly presented the Pope with a donation from his foundation and a hardback book jam-packed with Dutch painter Hieronymus Bosch's stunning art work.

Climate change is a subject very close to Leonardo's heart as he recently pumped $15 million from his own foundation to conservation projects around the globe.

The Hollywood hunk - who set up the Leonardo DiCaprio Foundation (LDF) in 1998 to protect the world's last wild places - confirmed his donation in the speech recently, insisting "generosity" is vital when it comes to the world's future.

LDF has awarded $30 million grants and supported more than 65 organizations since it was founded.