The 50th anniversary of rock 'n' roll is being marked on Monday, commemorating the date when Elvis Presley recorded his first single.
Presley played the song as an audition for Sun Studios head Sam Phillips
Musicians are gathering at Sun Studios in Memphis, Tennessee, where Presley first combined blues with rockabilly on the song That's All Right.
"It was a major moment in 20th Century culture," music historian Patrick Humphries told BBC Radio 4.
The song gets its first official UK release on Monday.
Radio stations around the globe will play That's All Right at 1600 BST on Monday, exactly 50 years after it was recorded.
Presley played the song with guitarist Scotty Moore and bassist Bill Black as part of an audition for Sun Records head Sam Phillips.
"Elvis had been running through some slow ballads," Phillips said, before his death in July 2003.
"We were getting ready to rack up and go home, Scotty was putting away his guitar.
That's All Right will be released in the UK with its original b-side
"All of a sudden Elvis would not take his strap off his shoulder and he came up with that song."
Moore said: "Elvis was just fooling around. He was just a white teenager rocking through an old black blues song he heard on the radio."
"It was cut in three or four takes. That was what we were looking for."
The song was taken to a Memphis radio station where it was played seven times in a row, prompting listeners to demand to know the identity of the singer.
A contrast to the safe, conservative songs popular at the time, That's All Right is regarded the birth of rock 'n' roll and Elvis Presley's spectacular career.
Thousands of rock 'n' roll fans, including pop star Justin Timberlake, are expected to gather at the Sun Studios site in Memphis on Monday.
The song will be released in the UK as a CD single and as a 10-inch vinyl record, with its original b-side Blue Moon of Kentucky. Only 5,000 copies will be pressed.
The vinyl release will be available only in HMV stores and will cost £3.99. If the record goes to number one, it will be Presley's 19th, a UK record.