Strictly Come Dancing favourite Debbie McGee has been injured ahead of Saturday night's show.
The current tip to win is said to be in "agonising pain" after going all out in training.
This weekend, Debbie and pro partner Gorka Marquez will perform the Samba to a Spice Girls Medley of Wannabe and Who Do You Think You Are.
But her sister Donna has revealed to the Daily Mirror newspaper: “She’s twisted a muscle so she’s struggling.
“It’s a real shame. She has been suffering – she had a hot water bottle on her back all week. It’s really been playing up.”
The news comes after Debbie said she was excited to head to Blackpool after previously performing in the city with her late husband.
Paul and I did a huge summer show at the Opera House, which has special memories for me as we sold out every night," she said.
Debbie has also lifted the lid on rumours of an unlikely romance between herself and pro partner Gorka.
She laughed off the rumours: “We have a very special friendship. People see us dancing these sexy routines and then we are pictured having lunch together so assume something must be going on.
“The truth is we really like each other but it isn’t a love affair. We love each other, but we are not in love with each other. It’s just one of those very special friendships. He’s 30 years younger then me!”
Speaking to the Daily Mirror newspaper, Giovanni added of their relationship: "I've got the winning partner, not just in this competition, but for the rest of my life."
All things going well, the remaining eight couples will take to the dancefloor this week when Strictly Come Dancing returns on Saturday 18th November at 6:45pm with the results show on Sunday 19th November at 7.15pm on BBC One.