"Wonderful Tonight" is a song written and performed by English singer Eric Clapton. The ballad was included on Clapton's 1977 album Slowhand. Clapton wrote the song on his 1974 Martin D-28 guitar about Pattie Boyd. The female vocal harmonies on the song are provided by Marcella Detroit and Yvonne Elliman. It peaked at number 16 on the Billboard Hot 100 on 15 July 1978, spending seven weeks in the top 40. In Canada it was in the top 40 for nine weeks. From Wikipedia
