Jason Momoa has poked fun at fellow movie superhero Chris Pratt for posing at the gym with a plastic water bottle.

The Aquaman star, who has launched a campaign to clamp down on the use of plastic, was horrified when his pal posted an Instagram shot of himself working out on Tuesday (03Dec19), and had to fire back.

"bro i love u but wtf (what the f**k) on the water bottle?" Momoa asked. "no single use plastic. come on."

The eco-warrior recently urged world leaders to step up their climate crisis efforts during a stern United Nations address, revealing "plastic pollution" is beginning to clog up the oceans and threaten livelihoods in the South Pacific.

"As a native Hawaiian born to a mother from Iowa, I have seen how one place can be oblivious to another," he said. "The issues facing an island can feel so far removed from that place that is landlocked in the middle of our country. However, with a foothold in two worlds, I quickly began to see how a problem for one will soon become a problem for all...

"We, the island nations and all coastal communities, are the front lines in this environmental crisis. The oceans are in a state of emergency, entire marine ecosystems are vanishing with the warming of the seas, and as the waste of the world empties into our waters, we face the devastating crisis of plastic pollution. We are a disease that is infecting our planet."

Momoa called on the leaders to honour the Paris Agreement and demand "global unity for a global crisis". Ironically, his own President, Donald Trump, pulled out of the Paris Agreement in 2017.