The Die Hard with a Vengeance star appears in a short film promoting The Climate Coalition's #Showthelove drive, urging citizens to display their support by wearing green heart badges.

Irons co-stars with actress Maxine Peake in the clip, which features a script by War Horse author Michael Morpurgo, and he wants fellow Brits to be more involved in environmental issues following the climate change conference in Paris, France last year (15) during which 195 nations agreed a deal to protect the planet.

"So much we love is under threat from climate change," he explains. "December's historic agreement in Paris might lead some people to believe that the job is done - but Paris simply set the direction of a journey we must now all take together. My grandchildren won't be safe and secure until we take proper care of our one and only planet."

A statement posted on the campaign's web page adds, "This February, thousands of people across the UK are turning hearts green to #showthelove for the people, places and life we want to protect for generations to come.

"The changes needed to protect our world have begun. We can have 100 per cent clean energy within a generation - but it needs us to show our love to make it happen... Will you share the promise and help protect all we love?"