The weather was damp and dreary, but inside the new 12South neighborhood hot spot he and wife Lauren frequent for the bar (they love the jalapeño margarita) and the tacos (duck for him, pork belly for her), the vibe was as warm and laid back as a day at the beach.
"I love celebrating No. 1 songs," the grinning singer, 25, told the crowd. Not to mention the three ACM nominations he received for New Male Vocalist, Album of the Year (for Tangled Up) and Single of the Year ("Die a Happy Man").
"I never in a million years would have thought a love ballad would be the biggest song of my career so far and stay number one as long as this one," he said of the tune, which topped the charts for six weeks. "But every line in that song is personal to my marriage, and to my wife, and it connects with fans in a big way."
Just days before, Rhett connected with fans in an up-close and personal way when he took a dive off the stage in Charlottesville, Virginia. "I was singing "South Side" and on the line where I say 'Shake your south side all the way to the floor' I tried to step out onto the guard rail, just missed it and I literally went all the way to the floor," he says.
"The crazy thing was none of the fans around me tried to help me up – they were all taking selfies with me while I was just lying there. To be fair, I'd probably do the same thing if Mick Jagger fell on the floor in front of me. It was only the second song of the show so I had 12 more to play after that."
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While "Happy Man" puts listeners in the mood for love, he says that his reputation as a romantic might be overrated. "All people see of me is what I put on Instagram so I'm only putting the highlights out there," he says. But he does follow some time-tested advice.
"I try to always abide by the old saying 'Act like you're dating your wife.' Just small things like when we check into a hotel there's yellow roses in the room because she loves yellow roses. I had a show on Valentine's Day this year in Los Angeles. We had all these big plans for that night but when we got to our hotel on the beach in Santa Monica, we checked in and went up to the rooftop with a drink. It was so great that we canceled everything and stayed up there until about midnight. It was one of the most special Valentine's ever."
A recent Nashville encounter with pal Dierks Bentley might not have been as special, but definitely as memorable.
"I ran into Dierks in Kroger recently. We talked for a while then I took off. I wasn't gone far when he called and asked, 'Have you left? I forgot my wallet. Can you spot me about $10?'" Rhett tells PEOPLE. "I drove back and he was waiting on me at the door. I didn't have any cash so I had to go to the check out with him and swipe my debit card for him. I felt like his dad. He still owes me the money."