Jason Momoa has been made an Advocate for Life Below Water by the United Nations

Speaking at the summit in Lisbon, Momoa said: "With this designation, I hope to continue my own journey to protect and conserve the ocean and all living things on our beautiful blue planet, for our generation and the generations to come."

On growing up in Hawaii, the 42-year-old actor continued: "For me, the ocean is an ancient teacher, a guide and a muse. It is also existential. Without a healthy ocean, life on our planet as we know it would not exist."

The 'Game of Thrones' star was applauded for his advocating as he was welcomed into the "UN family".

UNEP's ex ecutive Director, Inger Andersen, said: "In 2021, the four primary measures of climate change - greenhouse gas concentrations, sea level rise, ocean temperatures and ocean acidification - all hit record highs. This means the time for action is now."

UN Secretary General António Guterres warned attendees we are facing an "Ocean Emergency".

He said: "Sea levels are rising. Low-lying island nations face inundation, as do many major coastal cities in the world. The climate crisis is also making the ocean more acidic, which is disrupting the marine food chain. Ever more coral reefs are bleaching and dying.

"Nearly 80 per cent of wastewater is discharged into the sea without treatment. And some 8 million tons of plastic waste enter the oceans ever year. Without drastic action, this plastic could outweigh all the fish in the oceans by 2050."

Momoa stars as the titular superhero in the DC franchise, who has the ability to communicate with sea creatures.

The sequel, 'Aquaman and the Lost Kingdom', is slated for release on March 17, 2023.