The best man's speech at a wedding can contain anything, from playful jokes at the groom's expense, to more serious reflections on the couple and their married days ahead. However, in the case of Brett Eldredge's recent turn as a best man—for his older brother, Brice—none of these traditional routes would do.

Eldredge shared his unique "best man's speech" to Instagram, and as fans may have guessed by now, he chose to write a special song for his brother's special day, rather than read from a piece of paper.

"I woke up very emotional in the middle of the night a few months ago with the realization that my big brother was about to get married and that we were no longer kids anymore," the singer captioned his post. "I had been putting off writing my best man speech until it came to me at 3am and I wrote the whole thing in bed that night."

Watch above as Eldredge tells the reception guests, "I was supposed to write a speech, but I was like, screw that, I'd rather write a song," then launches into a real heart-tugger, with lyrics such as "When you start a family of your own / Hope your kids run wild like we did back at home / Barefoot in the grass / Never thinking we would grow up fast / And then we did."

The post also includes a picture of the two siblings in their formal wear, posing on the beach. "My brother is a great man and is my first call when life comes at me sideways. He and his incredibly smart and beautiful wife Lori are gonna have an awesome life together and I couldn’t be more happy for them," Eldredge writes. "I didn’t write [the song] for an album or any project, I wrote it for my brother, and though it’s almost impossible to sing through the tears, hopefully you will at least hear my heart for my brother, my best friend."

Eldredge is currently on his holiday Glow Live Tour, which will take him to select cities through Dec. 21.

Brett Eldredge Totally Turned This Fan Surprise Upside Down