He was sitting on the edge of the stage crooning "You Are So Beautiful," a Joe Cocker song, for his daughters, and wife, Faith Hill. When a girl joined him on stage he embraced the moment, and her.
Fan Kelly Samford Halcomb shot a cell phone video of the end of the serenade and posted it to Facebook. It's gone viral from there, showing McGraw hugging the girl, who has Down Syndrome, then signing his acoustic guitar and handing it to his fan with another big hug and a kiss.
Although you can't hear her reaction over the noise of the crowd, you can lip-read the smiling special fan as she says, "Oh my God."
Samford Halcomb, who captured it all on her phone, said: “Why I love Tim McGraw and country music.”
The star's generosity also helped lift the spirits of Samford Halcomb, who said on Facebook that she'd gone to the concert to cheer herself up after the death of her dog, a yellow lab named McGraw.
"I am honored to have captured such a special moment," she wrote of the McGraw's serenade.