Who Sings That Song "Express Yourself"?

Alright, So I Was Playing Driver Parallel Lines And It Takes Place In The 1970's So All The Music Played In The Game Is From The Seventies And Particularly 1979. The Song Repeated The Phrase "Express Yourself" Often And Has A Sort Of Funk, Jazz, And Disco Sound. I Have Searched Around For The Songs Real Name And Singer But All I Could Find Was Madonna And It Is Not The Right Song. I Know It Is A Real Song Because I Have Also Downloaded Other Songs From The Game Like The 1979 Huge Hit "Peaches" By The Stranglers. That Is All I Got. Help Me?