First recorded by Sheena Easton (1987).
Hit version by Celine Dion (MOR #22/CAN #16 1991).
From the wiki: “‘The Last to Know’, written by Brock Walsh and Phil Galdston, was first recorded by Sheena Easton for her 1987 album, No Sound But a Heart.
“Canadian singer Celine Dion covered ‘The Last to Know’ for her first English-language album, Unison (1990), produced by British record producer, Christopher Neil. The song was released by Columbia Records as the album’s fourth single in Canada in March 1991. Later, in September, it was issued as a single in the rest of the world. While not charting in the Billboard Hot 100, Dion’s recording did chart Top-20 in Canada and on the US Adult Contemporary music chart.”
Celine Dion, “The Last to Know” (1990):