Marion Cotillard has vowed to help "protect" the planet as she embarked on a Greenpeace expedition to the Antarctic

She said in a statement: "The Antarctic is a frozen wilderness that should be far beyond the reach of human impact, but even the most remote parts of our planet are changing at an alarming rate.

"It's the first time I've ever lived on a ship, and it's amazing to spend time with the Greenpeace crew and the scientists who are out here doing crucial work to understand the threats facing the oceans, like climate change, industrial fishing and plastic pollution.

"Our planet is a blue planet: the ocean covers more of it than every continent combined. We all have a responsibility to protect it."

Marion, 44, and her celebrity pals travelled on the Greenpeace ships Esperanza and the Arctic Sunrise, which were part of a four-week expedition in which six scientists from Stony Brook University and Northeastern University in the US conducted research to see how human activities are transforming the area.

Greenpeace oceans campaigner Louisa Casson said: "Oceans across the world are under increasing pressure and the Antarctic is no exception.

"The threats facing this remote wilderness give greater urgency to our call for a strong global ocean treaty and the creation of a global network of ocean sanctuaries that allow marine life to thrive."

The voyage is the last stop on Greenpeace's Pole To Pole expedition from the Arctic to the Antarctic, to promote a new United Nations global ocean treaty.