Here’s the theme song from a movie I’ve never seen: 1981’s Arthur, which starred Dudley Moore, John Gielgud, and Liza Minelli. I knew about Dudley Moore, not so much about the other two. It got 6.9 out of 10 stars by people who rated it on IMDb.
Anyway, the theme was written and performed by Christopher Cross, who had the music world on a string until MTV came along. The song reached #1 on the Billboard Hot 100 and the Adult Contemporary chart in the US, #2 in Canada, #7 in the UK, and #1 in Norway. He’s still recording, bless him, with his most release being 2017’s Take Me As I Am, on Christopher Cross Records.