Answer
Elaine Paige released "I Know Him So Well" with Barbara Dickson. The song was written by Björn Ulvaeus and Benny Andersson, and was first recorded by ABBA for the 1980 musical "Chess". It was later covered by Paige and Dickson for their 1981 album "Together". The song was a major hit for both artists, and has since been covered by a number of other artists.