The U.K. edition of Simon Cowell's music talent show "The X Factor" has announced that auto-tuning software will not be used on contestants' voices in future.

Earlier this week, "X Factor" bosses came under fire from viewers for allegedly tweaking the vocal performance of teenager Gamu Nhengu, when she sang a version of the Katrina and the Waves hit "Walking on Sunshine" during the opening show of the seventh series.

Producers of the show subsequently admitted that, in line with standard television practice, sound filters were used to remove background noise, but insisted they were not employed to give contestants a competitive advantage.

Now "X-Factor" bosses have pledged that auto-tune technology will not feature in any future shows, which are broadcast on ITV1.

"There will be no auto-tune in the audition shows or for competitive performances on live shows," a spokeswoman told the BBC.