One Day as a Lion was an alternative rock supergroup that was started in 2008 by Zack de la Rocha, the vocalist of Rage Against the Machine, and Jon Theodore, former drummer of The Mars Volta and current drummer of Queens of the Stone Age. The duo blended elements of rock and hip hop. One Day as a Lion released their eponymous debut EP in July 2008 on the Anti- label. The band's name comes from a quote by Benito Mussolini: "It is better to live one day as a lion than 100 years as a sheep."

Zacharias Manuel de la Rocha is an American musician, singer, songwriter, rapper, and political activist. He is best known as the vocalist and lyricist of the rock band Rage Against the Machine. Through both Rage Against the Machine and his activism, de la Rocha promotes left-wing politics in opposition to corporate America, the military-industrial complex, and government oppression.