The PETA organisation, which rallies against the cruel treatment of animals, crowned the two stars following an Internet survey.
Red Hot Chili Peppers frontman, Anthony Kiedis, recently became a vegetarian after his doctor advised his son to follow a vegetarian regiment.
Leona Lewis has been a long-time vegetarian. Additionally, she is also committed to stand against animal cruelty. The singer, who released the album Spirit, does not wear any clothing, shoes or accessories made from animal skin.