Cher’s 'Believe' was a massive comeback hit that fundamentally changed the sound of modern pop. At the age of 52, Cher became the oldest woman to have a number-one hit on the Billboard Hot 100. The song is most famous for its pioneering use of Auto-Tune as a creative vocal effect, rather than a corrective tool. This 'robotic' vocal sound was initially a secret; her producers told the press they had used a vocoder to keep other artists from copying the technique. The effect became known as the 'Cher Effect.' The song topped the charts in 23 countries and sold over 11 million copies. Its success led to the widespread use of Auto-Tune in hip-hop and electronic music, most notably by artists like T-Pain and Kanye West. It remains the best-selling single by a solo female artist in the history of the UK charts.