Here is a 1976 interview with Tillman Franks that appeared in the British magazine ‘Country Music People’. Here’s a partial transcription of the interview on how Elvis came to the Louisiana Hayride, by Tillman Franks:
“Jimmy and Johnny had a song called “If You Don’t Somebody Else Will”. It was Jimmy Lee and Country Johnny Mathis, and they were tremendous entertainers. They were the only one, and as a matter of fact I was booking (them) at the time and I had got them on Chess Records.