Country singer Kacey Musgraves posted a sweet tribute for her boyfriend Cole Schafer, who celebrated his 29th birthday Thursday.

"Happiest birthday to the brightest flame in my world. My deeper well. I love you, @cole_schafer. You are such a fixture in the lives of all the people who are lucky enough to really know you," the 34-year-old Grammy-winning singer wrote alongside a set of photos showing her and Schafer in light moments. The gallery included a photo showing Schafer playing the guitar and another showing him smiling sweetly before the camera as the singer planted a kiss on his cheek.

The "Rainbow" singer also highlighted the things she is grateful about Schafer and said, "So grateful for all the laughs and adventures, deep talks, ego checks, wise advice, forehead kisses, the books you recommend, your late late-night just whipped this up" and somehow it's extremely gourmet pasta (like, actually Michelin star) situations, the gorgeous way you observe the world and the words that follow."

Musgraves concluded her post by highlighting the sexiest thing about her Nashville-based boyfriend by writing, "Mostly your unabashed, full-throttle vulnerability which is easily the sexiest thing about you. I can't wait to see what this year brings to you."

Musgraves formally ended her marriage with Ruston Kelly in 2020, and in June 2021, she was spotted strolling the streets of New York City with Schafer.

In an interview last August, the "Star-Crossed" singer said she and Schafer locked eyes in a crowded restaurant. Schafer did not know who she was, which made her like him even more.

"He did not know who I was, which I loved," she told the New York Times.

In another interview last March 2022, Musgraves reveled her relationship with the writer and said, "I don't really want to keep things private, because I'm proud of the love that I have. I'm very happy. It's natural to want to share that. And I don't want to come across like a robot — I think people like me because I share who I am."

Musgraves added, "I feel really lucky to be with someone who is so secure and is a champion of me reaching for every star possible."

Kacey Musgraves
Kacey Musgraves is pictured performing at the Theatre at Ace Hotel on Feb. 14, 2019 in Los Angeles.  Kevin Winter/Getty Images