X Factor girl group Rhythmix have been forced to change their name mid-series due to it already being trademarked to a Brighton charity.

The four-piece will now experience a  rebranding after the children’s music charity Rhythmix wrote an open letter to X Factor kingpin Simon Cowell via Facebook.

Rhythmix is a charity that helps vulnerable young people to create and perform their own music.

The girl group’s new name has not been released and is expected to be revealed on Saturday night’s live show.

Chief executive Mark Davyd claimed that Cowell’s company Simco had applied to trademark the name Rhythmix while aware that it was already in use by the charity.

“Rather than seeking any discussion with the Charity, considering any of the moral implications of their actions, or checking with the Charity whether the pursuit of an exclusive trademark might have a negative impact on the activities of the Charity, Simco and their legal representatives apparently sought a way to use the law to circumvent the trademark of the Charity,” Davyd wrote in the letter.

He praised Cowell’s charity work but said the the TV show’s decision to use the name threatened the charity’s work.

“We don’t buy this media invention of you as Mr Nasty. Your Wikipedia entry explains at length your involvement with children’s charities and we commend you for it.

“”Rhythmix the charity has worked with over 40,000 young people in the last twelve years,” Davyd wrote. “All of that work is placed at risk by the actions of your company.”

Davyd ended the letter with a simple and blunt request to Cowell that said: “Just change the name.”

Last night, X Factor producers issued a statement that said: “At the request of the charity Rhythmix, the members of the girl group Rhythmix have decided to change their name, a decision which has the support of Syco and TalkbackTHAMES.”

The publication of the letter followed the initiation of a Facebook campaign supporting the charity, which gained over 65,000 followers.

The group urged also music fans to download Nirvana’s 1991 track Smells Like Teen Spirit this December, thereby ensuring an X Factor contestant would not make Christmas number one.