Jonathan Leonard Friga, known professionally as Jonathan Cain, is an American musician, singer and songwriter. He is best known as the keyboardist and rhythm guitarist for Journey. He has also worked with The Babys and Bad English. Cain was inducted into the Rock and Roll Hall of Fame as a member of Journey in 2017. He also maintains a solo career as a contemporary Christian artist.

"Faithfully" is a song by American rock band Journey, released in 1983 as the second single from their album Frontiers. The song was written by keyboardist Jonathan Cain. It peaked at number 12 on the Billboard Hot 100, giving the band their second consecutive top-twenty hit from Frontiers. Despite featuring no chorus, it has gone on to become one of the band's most recognizable hits and has enjoyed lasting popularity. In a Classic Rock article, "Faithfully" was called the greatest power ballad ever recorded.