To the best of my knowledge (1984 Culture Cmub concert Sydney, Australia!) it's Helen Terry on backing vocalsThe ephemeral Monroe Paradox has been mentioned before - I saw this question, immediately thought of this song, then heard the last line of 2nd verse.
Full version for those of us who may have forgotten quite how good Culture Club and Boy George were. Katy Brand is kiilling it on the backing vocals too.
https://www.youtube.com/watch?v=z_xU6hkdgAw