Thomas Walter Hampson (born June 28, 1955) is an American lyric baritone, a classical singer who has appeared world-wide in major opera houses and concert halls and made over 170 musical recordings. Hampson's operatic repertoire spans a range of more than 80 roles, including the title roles in Mozart's Don Giovanni, Rossini's Guillaume Tell and Il barbiere di Siviglia, Thomas' Hamlet, and Tchaikovsky's Eugene Onegin. The center of his Verdi repertoire remains Posa in Don Carlo, Germont in La traviata, the title roles in Macbeth and Simon Boccanegra, and more recently also Amfortas in Wagner's Parsifal and Scarpia in Puccini's Tosca. As a recitalist Hampson has won worldwide recognition for his thoughtfully researched and creatively constructed programs that explore the rich repertoire of song in a wide range of styles, languages, and periods. He is one of the most important interpreters of German Romantic song – especially known for his interpretations of the music of Gustav Mahler – and, with his "Song of America" project collaboration with the Library of Congress, has become known as the "ambassador" of American song.