Glen Campbell recorded his final song, 'I'm Not Gonna Miss You,' in January of 2013, as the effects of Alzheimer's were robbing him of his abilities to sing, play guitar and complete daily tasks. Since the country legend is unable to perform the song live, due to the debilitating disease, his son Shannon has released a video of himself performing the tune in the attic of his father's house as a tribute.

The younger Campbell delivers the song's poignant lines like, "I'm still here, but yet I'm gone / I don't play guitar or sing my songs / They never defined who I am / The man that loves you 'til the end / You're the last person I will love / You're the last face I will recall / And best of all, I'm not gonna miss you / Not gonna miss you," with such raw and tender emotion that it's clear it's a message he has been coming to terms with for a long time.

The song was included in the documentary, 'Glen Campbell ... I'll Be Me,' which chronicles Campbell, along with his family, dealing with the rapid progression of his Alzheimer's. Shannon Campbell, who, together with his siblings Ashley and Cal, performed in his father's band until he was forced to retire, got a firsthand look at the final farewell.

"I thought it was amazing when we were on tour, the people who would show up at the shows and watch and just kind of see him play one last time," Shannon tells Rolling Stone Country. "Brad Paisley came to the show and came backstage and talked to us. It was just amazing the people that got to be in the documentary, too."

'I'm Not Gonna Miss You' earned an Oscar nomination for Best Original Song, as well as two Grammy nods, for Best Country Song and Best Song Written for Visual Media. The music video received an ACM Awards nomination, for Video of the Year.

Download the 'Glen Campbell ... I'll Be Me' soundtrack here.