Conversation so far:
When did Burt Bacharach start working as a musician?
Following his tour of duty in the United States Army, Burt Bacharach spent the next three years as a pianist and conductor for popular singer Vic Damone.

Question: What years was that?
Self-contained rewrite: What years was that when Bacharach spent the next three years as a pianist and conductor for popular singer Vic Damone?