Willie Nelson - Always On My Mind (Official Video)

I know this song from the Lynne Marie Stewart tribute in It's Always Sunny in Philadelphia

Counter with Ryan Adams:

https://youtu.be/3VJ0rwQTNTE

Better vocal performance imho

Originally recorded separately by Brenda Lee and Gwen McCrae almost at the same time, as was tradition back then, and made popular by Elvis Presley. But personally I'm fond of the version by Pet Shop Boys.