"Probably not gonna be nominated for musical duo of the year, but you never know," Brad Paisley posted on Twitter early Sunday morning, along with a photo of himself performing the night before with Denver Broncos quarterback Tim Tebow. The country star invited the football star on stage at the Mile High City's Pepsi Center to sing with him on 'I'm Still a Guy.' (Watch a fan's footage of their performance below.)

"We've seen you throw an 80-yard touchdown pass, but can you sing?" Brad asked Tim. The 24-year-old gridiron great was all smiles, but a bit hesitant to take the mic. (You'll see why when you watch the duet!) But he did, and regardless of his musical fumble, he was praised with deafening cheers.

"Thanks for singing with me @TimTebow. But don't quit your day job pal," Brad tweeted. "'Still a Guy' has never been so exciting. Or quite so beautifully off key."

Brad's Virtual Reality tour, also featuring the Band Perry and Scotty McCreery, continues this Thursday in Boise, Idaho. See a full list of tour dates here.