Craig Morgan stopped by The Kelly Clarkson Show to promote his single, "The Father, My Son and the Holy Ghost," and talk about his late son, who died three years ago. He had no idea he'd be seeing one of his good friends and biggest supporters, Blake Shelton, who was waiting in the wings to surprise him.

"I was so moved by it [the song] that I wanted to surprise you, so I have someone here to see you... come on out, Blake," Clarkson told Morgan, yelling at Shelton to make his entrance.

Morgan wrote the song after his 19-year-old son Jerry, died in a tubing accident in July of 2016. Shelton has felt the pain of loss, too — his brother, Richie, died when he was a kid — but The Voice coach says his friend's song impacted him not because he could relate.

"Gwen and I were actually at the funeral [of Morgan's son] and I didn't connect it to anything ... it was his story and it hit me that hard just knowing him," Shelton explains.

WATCH: Craig Morgan Is Ready to Talk About His Son, Jerry

Morgan actually sent the song to Shelton, who didn't respond for a month.

"I'm a great friend," Shelton jokes. "When the kids are around I have zero access to my phone, and I even knew that there was an attachment there but I couldn't get my phone back."

When he finally did listen? "I was by myself at the house and I lost my mind," Shelton admits.

Morgan and Shelton's visit to Clarkson's show was a reunion, as they haven't seen each other since "The Father, My Son and the Holy Ghost" was released.

With help from his friend Shelton, Morgan's single reached No. 1 on iTunes' all-genre chart — something highly unprecedented for any country artist, much less one who hasn't been in the spotlight in some time. Shelton created an online campaign to get fans to listen and purchase the song, and his outreach even got to Ellen DeGeneres.

Morgan debuted the heart-wrenching song live at the Grand Ole Opry this past July, and released it officially on Aug. 30 as his first new single in the three years — the first since his son's death.

Blake Shelton Helped Craig Morgan Get to No. 1: 

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