More than 1,250 US radio stations have celebrated a defining moment in rock 'n' roll by simultaneously playing Elvis Presley's debut single.
Presley played the song as an audition for Sun Studios head Sam Phillips
That's All Right was recorded by Presley at Sun Studio in Memphis, Tennessee, 50 years ago on Monday.
His guitarist Scotty Moore played a recording of the song from the studio, broadcast across the US by satellite.
Up to 8,000 fans gathered in Memphis for the anniversary including musicians Isaac Hayes and Justin Timberlake.
In the UK, the anniversary was celebrated with the release of a special collector's edition of the track That's All Right Mama.
Never previously released in the UK, the single is already at number two in the UK midweek singles charts.
Some global radio stations were also able to receive the broadcast of That's All Right at 11am local time (1600 BST) on Monday.
Combining blues with rockabilly, the song is widely accepted as the first rock 'n' roll single.
The broadcast kicked off a full day of music featuring Memphis greats and others.
Moore began the live music with a band featuring Presley's first drummer, DJ Fontana, songwriter and musician Billy Swan plus country musician and Elvis tribute artist Ronnie McDowell.
When asked if he knew he was about to change the musical world when he recorded That's All Right 50 years ago, Moore replied: "You gotta be kiddin'. I already had a band and my only ambition was to play music."
Moore and Presley played the song with bassist Bill Black as part of an audition for Sun Records head Sam Phillips.
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."