Shelton told DeGeneres that Stefani's brother Todd helped make the music video while the family stayed indoors due to the COVID-19 pandemic.
"Gwen has these five years worth of home video on her phone and so Todd got the camera out and we shot a few setups of us singing the song and he edited that thing and put the video together," Shelton said.
"It ends up being maybe my favorite video I've ever had just because it's so honest and real," he continued.
The country star also discussed his greying hair and how Stefani had once dyed it.
"I would have really liked it better had I not gained 117 pounds during the quarantine. I thought it made me look younger, but I was still just as fat. Now I'm actually trying to lose weight," Shelton said.
"I'm not opposed to having her color my hair again. I don't care. If it makes her happy, I'm cool with it," he continued.
Shelton and Stefani started dating in 2015. Stefani referred to the singer as her "best friend" in June while celebrating his 44th birthday.