Louisa Johnson has sparked fears she could miss 'The X Factor' final.

Louisa Johnson

Louisa Johnson

The blonde beauty is set to battle Che Chesterman and Reggie 'N' Bollie to be crowned winner of the current series of the singing competition this weekend, but has been forced to pull out of a performance scheduled for tonight (09.12.15) after falling ill.

She wrote on Twitter: "so sorry that im missing tonight in liverpool! Need to be on strict voice rest ahead of the biggest week of my life, it needs to be perfect (sic)."

The 17-year-old singer has been favourite to win the competition since it kicked off earlier this year, and bosses are now said to have ordered her to rest up ahead of the final.

An 'X Factor' spokesperson told Metro.co.uk: "Unfortunately Louisa is unwell and we have been advised by doctors that she currently needs to be on bed and voice rest ahead of this weekend's final. We're sorry to disappoint anyone who was looking forward to supporting her at her performance in Liverpool today."

'The X Factor' final airs Saturday (12.12.15) and Sunday (13.12.15) at 8pm on ITV.