"Rockabilly" usually (but not exclusively) refers to the type of rock and roll music which was played and recorded in the mid 1950s by white singers such as Elvis Presley, Carl Perkins and Jerry Lee Lewis, who drew mainly on the country roots of the music. Many other popular rock and roll singers of the time, such as Fats Domino and Little Richard, came out of the black rhythm and blues tradition, making the music attractive to white audiences, and are not usually classed as "rockabilly".
In July 1954, Elvis Presley recorded the regional hit "That's All Right (Mama)" at Sam Phillips' Sun Studio in Memphis. Three months earlier, on April 12, 1954, Bill Haley & His Comets recorded "Rock Around the Clock". Although only a minor hit when first released, when used in the opening sequence of the movie Blackboard Jungle, a year later, it really set the rock and roll boom in motion. The song became one of the biggest hits in history, and frenzied teens flocked to see Haley and the Comets perform it, causing riots in some cities. "Rock Around the Clock" was a breakthrough for both the group and for all of rock and roll music. If everything that came before laid the groundwork, "Rock Around the Clock" introduced the music to a global audience.