The longtime couple, who are rumoured to be engaged, camped out for two days together in California’s Death Valley and drank only water produced from the emissions of their B-Class, F-Cell car – a vehicle that runs on hydrogen fuel cells and electricity.
The pair has been driving their F-Cells for more than two years and are vocal advocates for reducing C02 emissions.
As the lowest and driest area in North America, Death Valley is known as one of the hottest places on earth.
“That’s crazy… our car makes water!” says the Canadian actor, 35, as he drinks the car’s emissions for the first time in the desert heat.
“We’re saved!” adds Diane, 37.
Watch the “death defying” video below.