Frankie Valli (born Francesco Stephen Castelluccio; May 3, 1934) is an American singer, known as the frontman of The Four Seasons beginning in 1960. He is known for his unusually powerful head voice. Valli scored 29 Top 40 hits with The Four Seasons, one Top 40 hit under The Four Seasons alias The Wonder Who?, and nine Top 40 hits as a solo artist. As a member of The Four Seasons, Valli's number-one hits included "Sherry" (1962), "Big Girls Don't Cry" (1962), "Walk Like a Man" (1963), "Rag Doll" (1964) and "December, 1963 (Oh, What a Night)" (1975). Valli's recording of the song "Can't Take My Eyes Off You" reached number two in 1967. "You're Ready Now", a Valli solo recording from 1966, became a surprise hit in the UK as part of the Northern soul scene and hit number eleven on the British pop charts in December 1970. As a solo artist, Valli scored number-one hits with the songs "My Eyes Adored You" (1974) and "Grease" (1978).
Valli, Tommy DeVito, Nick Massi and Bob Gaudio – the original members of The Four Seasons – were inducted into the Rock and Roll Hall of Fame in 1990 and the Vocal Group Hall of Fame in 1999.