For Erin and her family, the song "You'll Never Know This" has always held special meaning.
Her grandmother Laura used to sing it to her grandfather Howard when he went off to fight in World War II. Ever since then, it has been the family's favorite love song.
The couple had been married for 73 years, but as Laura lay on her deathbed, 92-year-old Howard chose to sing this love song to her one last time.
Captured on video by their daughter Erin, Laura can be seen lying in a hospital bed, surrounded by friends and family, as Howard sings the ballad to the love of his life.
It's a moment that would touch even the hardest of hearts, a final declaration of love through song.
Watch the tear-jerking moment in the video below