Shannon Leto is an American musician best known as the drummer of rock band Thirty Seconds to Mars. He co-founded the group in 1998 in Los Angeles, California, with his younger brother Jared. Their debut album, 30 Seconds to Mars (2002), was released to positive reviews but only to limited success. The band achieved worldwide fame with the release of their second album A Beautiful Lie (2005). Their following releases, This Is War (2009) and Love, Lust, Faith and Dreams (2013), received further critical and commercial success. As of September 2014, the band has sold over 15 million albums worldwide.

Thirty Seconds to Mars is an American rock band from Los Angeles, California, formed in 1998. The band consists of brothers Jared Leto and Shannon Leto. During the course of its existence, it has undergone various line-up changes with the Leto brothers being the only consistent members.