One of the beautiful songs. And look at how few instruments it took to make it: lead vocal, backing vocals, guitar, piano, double bass, drums. With so many rich possibilities to overproduce a song as sentimental and with such sublime chord and melody ideas as this, Elvis and his team kept the song minimal.
And what do you get? Intimacy! The very thing the song is about.
I don't know if the King had a better vocal performance anywhere in his canon.
Made for a cheap film, the song definitely outlived its original obligation.
And happy Valentines Day!