City Car Club, a carshare operator established in 2000 and based in the U.K. operates a fleet of vehicles including many Honda Civic Hybrids. The carshare group recently polled celebrities to find out what kind of vehicles they drive. Afterwards, the average CO₂ emissions of their fleets were summed up and the celebs were ranked. The worst of the worst turns out to be Simon Cowell, the judge you know and love from American Idol. Apparently, the Bugatti Veyron, Ferrari F430 and Rolls Royce Phantom in his garage average 457 g/km of CO₂, with the Veyron emitting the most at a whopping 574 g/km.

Jay Kay, "that bloke what wears daft stuff on his head" and frontman for the funk band Jamiroquai comes in at second place, followed by soccer star David Bekham. We're not really sure just how exhaustive the City Car Club's list is, but check out the top bottom ten after the break. American celebs appearing on the list include rapper fiddy 50 Cent and singer Justin Timberlake.