Conversation so far:
What was Bob Crewe's career like in the 1950s?
In 1953, Bob Crewe met and partnered professionally with Frank Slay Jr., a young pianist from Texas.
was their anything significant about Bob Crewe and Frank Slay Jr. in the 1950s?
Bob Crewe and Frank Slay Jr.'s collaboration created several hit songs, for which Crewe performed as the demo singer.
what were some of the hit songs by Bob Crewe in 1950s?
some hit songs by Bob Crewe in the 1950s include Silhouettes and Daddy Cool

Question: who else sang on the songs?
Self-contained rewrite: who else sang on Bob Crewe's songs?