Sienna Miller, Sir Paul McCartney and Lily Cole are backing the U.K.'s new Climate Week initiative to raise awareness of environmental issues.
Mark Ronson, designer Vivienne Westwood and TV presenter Michael Palin are also supporting the scheme, which aims to encourage more Brits to go green to help the planet.
Climate Week founder Kevin Steele tells WENN, "We are delighted that people such as Sir Paul MCCartney, Sienna Miller, Lily Cole and Mark Ronson are backing Climate Week.
"Their support is a vital part of showing how everyone can do their bit to combat climate change. With the energy and influence of the biggest names in entertainment, politics and business, Climate Week can help inspire millions of people to protect our planet and create a secure future."
Climate Week takes place in Britain between 21 and 27 March (11).