How to do a Duet

With our current lunch time movie screening being a Chinese serial, I decided to supplement my home-cooked meal with You Tube. Here's Cliff and Olivia doing Suddenly; they've got such a deep friendship which is so evident. I saw this performed live and that memory will stay with me a long time.

http://www.youtube.com/watch?v=AcUVa2CWDnk