"Hope you know how lucky the world is to have you in it, @rustonkelly," she wrote, adding, "Happy Birthday! I’m in your corner." In the pic, Kelly's back is turned and he is looking out a window.
The musicians tied the knot in Tennessee in October 2017. On July 3, the pair announced that they were separating after almost three years of marriage.
According to court docs obtained by ET, Musgraves filed for divorce on July 2, citing irreconcilable differences.
“With heavy but hopeful hearts we wanted to put our own thoughts into the air about what’s happening," the two said in a joint statement given to ET. "These kinds of announcements are always met with scrutiny and speculation and we want to stop that before it even starts."
"We believe that we were put into each other’s lives for a divine reason and have both changed each other infinitely for the better," the announcement continued. "The love we have for each other goes far beyond the relationship we’ve shared as husband and wife. It’s a soul connection that can never be erased."
While they are separated, the two have exchanged kind messages to one another on social media. Musgraves supported Kelly when his song, "Pressure," dropped last month.
"This song, y’all," Musgraves tweeted along with a weary face emoji. Kelly replied to his ex, adding, "u convinced me to [black heart emoji]."