Who coined the phrase 'If it feels good do it'?

Don't know where it started but the rendition that always comes to mind for me was by a soul songstress in the 1970s. (Sadly can't remember her name, been googling for it but all I get is references to George W Bush - anyone?) Anyway, BBC Radio 1 DJ Alan Freeman (who passed away recently) used to use a snatch of the song as a jingle and it became an anthem for his show and his fans. Yay!