Guess Who This Lil' Singing Cowboy Turned Into!

Before this kid saddled up for the big stage, he was just rockin' his cowboy gear in San Antonio, Texas ... and covering Justin Bieber's "Mistletoe" on YouTube back in 2010.

He's collaborated with music's hottest stars like Pitbull ... "Mmm Yeah!" ... and has 11+ million Instagram followers.