Sunday Morning Extra The country music duo Brothers Osborne's success in Nashville wasn't assured until their joined together. They tell Anthony Mason the moment they knew they had made it in the music biz. https://cbsn.ws/2QBuUCY | CBS Sunday Morning

As far as Bluegrass songs are concerned, this is probably the most well known of them all. If nothing else, it has become one of Tennessee's state songs and hundreds of thousands of Tennessee Volunteers sports fans sing the song week after week. This is largely thanks to not only The Osborne Brothers, but Lynn Anderson, who did a cover, and Boots Randolph as they garnered the attention of UT band arranger, Barry MacDonald. Watch this video of The Osborne Brothers performing their hit song, "Rock