Former Coronation Street actress Tina O'Brien will sit out this Saturday's Strictly Come Dancing after being diagnosed with chicken pox.
O'Brien, 27, and her professional dance partner Jared Murillo will be sent straight through to the following week's edition of the BBC One show.
The other couples will dance as usual with one pair leaving the contest.
But the show's rules state that if O'Brien is unable to dance for a second week she will have to leave.
"I am devastated. I was so looking forward to this week's show," the actress said.
"Jared and I have spent so much time and effort on a really fantastic routine and I just couldn't wait to perform it on Saturday.
"Hopefully I will bounce back quickly and be on top dancing form soon, ready to come back straight into the next routine," she added.
A BBC spokeswoman said none of the other contestants had been affected.
"We've made people aware of the situation and told them if they start to feel unwell to contact their own doctor in the first instance," she said.
Meanwhile, former Conservative MP Ann Widdecombe will appear on this weekend's show despite the death of her brother on Tuesday.
The BBC spokeswoman confirmed the 63-year-old had been given the choice of whether to appear or not but decided to continue after speaking to her family who said they wanted her to carry on.
DJ and music producer Goldie and dance partner Kristina Rihanoff became the first couple to be eliminated from this year's show last week.