Mel B looks set to miss The X Factor finals after being treated in hospital for a mystery illness.

We told you yesterday how the judge had reportedly collapsed on Thursday night, after taking mentee Andrea Faustini to the Royal Albert Hall.

And now The Mirror reports that the former Spice Girls star is "seriously ill" and has been kept in overnight for tests.

Insiders are reported to have said it looks like she's 90 per cent certain to miss the big event.

A source said: "She is in hospital and is seriously ill.

"We are awaiting the result of tests and then we will know exactly what is wrong.

"If I had to predict it, having seen her, I don’t think she will be able to do the show.

"Miracles do happen and the doctors may say she is well enough to leave but, looking at her, I would be amazed if that happens."

And The Mirror also claims that former judge Tulisa will be called on as a substitute.

"Tulisa is really happy to help out," said a source.

"She knows how important it is for the contestants to have someone there mentoring them, and getting behind them, especially when it is so near to the final.

"She will be making sure that Andrea gets as much help and guidance as possible."

Fleur East is still leading the betting for the grand finale, with one punter reportedly staking a whopping £20k on her to triumph tomorrow night.