"What's in Our Heart" is a song written by George Jones and Johnny "Country" Mathis.
It was recorded and released as a B-side duet by American country artists George Jones (the song's co-writer) and Melba Montgomery.
The recording date was the second session that took place between Jones and Montgomery.
Other songs included on the session were "Let's Invite Them Over", "Suppose Tonight Would Be Our Last", and "I Let You Go".
The song received radio airplay and reached the twentieth position on the Billboard Magazine Hot Country Singles list.