Hardy, Wallen and Malone performed two of the late singer's hits at the CMA Awards on Wednesday.
Morgan and Hardy got the Joe Diffie tribute started, singing the late country star's 1993 hit "John Deere Green." Post Malone joined the group next, singing "Pickup Man," which Diffie, who died in 2020, released in 1994.
This was Post Malone's first-ever performance at the CMAs. This seemed inevitable, as Post Malone in the past has professed his love for the genre.
Earlier in the night, Wallen teamed up with Eric Church to perform their song, "Man Made a Bar."
Just last month, Hardy made an emotional return to his tour in Arkansas after he was forced to cancel some dates amid a health scare that landed him in the hospital.
"I'm going to try to get through this next without crying. Holy s**t," Hardy told the crowd. "First and foremost I wanna let everybody know I'm OK. I'm dealing with some stuff right now and I really hate that I had to do what I had to do last weekend, cancel shows. But it's something that I had to do for myself, and if you know me, you know how hard that was for me because I like to work."
"I'm not going to lie, I was really nervous before I walked on the stage," he said. "It might hit me before the show is over but as I got on the stage, something in my brain said, 'This is what you're meant to do and you're meant to be here tonight.'"