The two became friends when they competed on the show in 2012, until she suddenly quit during its live rounds - with programme-makers saying her departure was due to "illness".

Last year, Spraggan revealed in a memoir that she was attacked by a hotel porter after a night out celebrating Clark's birthday at a Mayfair nightclub, which was attended by members of The X Factor production team.

In a new interview, Clark, now a broadcaster and media personality, said it was a "horrendous" period and that he had kept the details "quiet" for 11 years.

"That was a really, really tough time," he told The Guardian. "It was horrendous and I've still not spoken about it because it's not my story to tell, even though I was part of it.

"As a 24-year-old, it was the night of my birthday, to wake up to your friend saying, 'I was raped last night', while being on the biggest show in the country while being followed by the press wherever you go... I don't know how I did it."

Clark, now 35, said Spraggan dubbed him Jessica Fletcher - Dame Angela Lansbury's character in Murder, She Wrote - because he leapt into action, telling TV researchers to "go and get the bosses" and making sure the hotel bedroom was not cleaned by staff, to preserve the crime scene.

"I became like a crime detective and I don't know why that was," he said.

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In her memoir, titled Process: Finding My Way Through, Spraggan said she had to take a drug used to prevent HIV, which made her too unwell to continue on the programme.

She also said the TV production team called the police and an arrest was quickly made, but she believed they were "unprepared" to deal with the situation.

Asked about it, Clark said: "There was a lot that could have been improved. I think everyone learned loads from those kind of mistakes, but I don't think it was anyone's fault other than the man who raped Lucy."

He added: "I've worked on reality shows for 12 years now, and I've seen the change in duty of care. It's everyone's priority now."

James Arthur was crowned the winner of The X Factor that year. Spraggan went on to have two top-10 albums in the UK charts, with Join The Club reaching seven in 2013 and Choices peaking at five in 2021.

A spokesperson for Fremantle, the British TV company that produced The X Factor for ITV under its Thames TV entertainment arm, previously described the assault on Spraggan as "a truly horrific criminal act for which the perpetrator, who was not connected with the programme, was rightfully prosecuted and imprisoned".

The spokesperson said: "Anyone should feel safe when they are sleeping in a hotel room and it is abhorrent to think that a hotel porter abused that trust in such a vile way.

"To our knowledge, the assault was an event without precedent in the UK television industry. Whilst we believed throughout that we were doing our best to support Lucy in the aftermath of the ordeal, as Lucy thinks we could have done more, we must therefore recognise this.

"For everything Lucy has suffered, we are extremely sorry. Since then, we have done our very best to learn lessons from these events and improve our aftercare processes.

"Whilst we have worked hard to try and protect Lucy's lifetime right to anonymity, we applaud her strength and bravery now that she has chosen to waive that right."