DiCaprio and Winfrey are the greenest stars

Leonardo DiCaprio and Oprah Winfrey are the greenest celebrities in the world, according to a new poll to unearth the most popular eco-friendly stars.

DiCaprio beat off competition from Bono, Brad Pitt and actor Ed Begley Jr to top the male category in the survey, which was carried out by GreenDaily.com and Bebo.com, to mark Earth Day on Wednesday.