Sienna Miller's green competition

Sienna Miller's green competition

Sienna Miller, Madonna and Leonardo DiCaprio will battle it out to be named the ultimate green celebrity.

Playhouse Disney's Playing for the Planet Awards has announced a shortlist of 10 stars who have been nominated for the Greenest Star prize for using their fame to promote environmental issues.

Sienna has been recognised for her work in raising awareness about global warming, while Leonardo is a tireless campaigner and donator to various green campaigns. The 'Departed' actor recently made a documentary 'The 11th Hour' about global warming.

Other contenders include British supermodel Lily Cole, who only works with environmentally friendly companies, and 'Harry Potter' actress Emma Watson, who has spent time working with the Wild Trout Trust.

Celebrity power couple Gwyneth Paltrow and husband Chris Martin also received a nomination.

The 'Iron Man' actress has been the face of US environmental campaigns to cut down the use of oil, while her Coldplay rocker spouse travels on an eco-friendly tour bus complete with recycling facilities.

Johnny Depp, designer Stella McCartney, 'Smile' singer Lily Allen and British actor David Tennant have also made the shortlist.

Viewers have until July 31 to vote for their greenest celebrity by visiting website www.playhousedisney.co.uk/playingfortheplanet.