Louis Walsh leaves The X Factor as show ushers in new era
The judge will step down from the panel and Sharon Osbourne will have a reduced role.
Louis Walsh has decided to leave The X Factor as the show ushers in a "new era", it has been announced.
The TV star has been the longest-serving judge on the talent show, appearing on all bar one series since the show began in 2004.
He will continue to serve as head judge on Ireland's Got Talent, production company Thames confirmed.
Walsh said in a statement: "I've had a fantastic 13 years on The X Factor but the show needs a change and I'm ready to leave.
"I'm looking forward to another series of Ireland's Got Talent, going back to my day job as a manager, writing my memoirs and seeing the world."
Sharon Osbourne will have a scaled-back role in the show when it returns for a 15th series later this year.
She will only appear as a judge during the live episodes, skipping the audition process of the series.
She said: "I can't wait to get back to the judges' desk. I love the new format."
The show's creator Simon Cowell will return to the show for the new series with three new fellow judges, who will be announced in due course.
Amelia Brown, managing director of Thames, said: "Louis has been a huge part of The X Factor's success since it launched and remains a good friend of the show.
"His contribution cannot be overstated. We would like to thank him for all he has given to the show over the years and look forward to continuing to work with him in the future."
She added: "We are very excited Sharon is taking on a new role on the show and we can't wait to see her as a judge on the live episodes.
"This is the start of a new era for The X Factor. I am really excited about all the ideas we have for the coming series including, of course, the new judging panel."
Judges' auditions for The X Factor 2018 will take place at Wembley Arena in London and previously advertised auditions in Liverpool will now take place at the venue in the capital.
More than 30,000 contestants have already entered the 2018 series after open auditions across the country.