Thomas William Hamilton (born December 31, 1951) is an American musician, best known as the bassist for the hard rock band Aerosmith. He has regularly co-written songs for Aerosmith, including two of the band's biggest hits: "Sweet Emotion" (1975) and "Janie's Got a Gun" (1989). Hamilton occasionally plays guitar (e.g. "Uncle Salty”, “Sick as a Dog"), sings backing vocals (e.g. "Love in an Elevator") and on rare occasions, lead vocals ("Up On The Mountain").