"That'll Be the Day" is a popular rock and roll song written by Buddy Holly and Jerry Allison. Released in 1957, it became one of Holly's most famous tracks, showcasing his distinctive vocal style and innovative sound. The song's catchy melody and relatable lyrics contributed to its success, making it a classic in the genre. The song was later covered by various artists, including The Crickets, the band Holly was part of, and The Beatles. Its influence can be seen in the development of rock music, and it remains a staple in the repertoires of many musicians today.