Craig Revel Horwood is suffering "immense pain" during 'Strictly Come Dancing' episodes after putting off a hip operation.
The 52-year-old show judge - a former professional dancer - is said to be battling to stay fit for the remainder of the series after being left in "complete agony" due to the injury.
A show source said: "He had a hip replaced in 2013 but now he needs the other one doing. Doing the smallest things causes him immense pain.
"He is fighting through it to see the rest of the series out."
Craig's hip injury was not helped by a fall on Saturday night's (21.10.17) show when he tumbled off his chair while doing an impression of fellow panellist Bruno Tonioli.
The source added to The Sun newspaper: "He may only have been larking around but he's actually in agony."
In 2014, Craig revealed undergoing a hip operation had changed his life, and he blamed the injury on dancing, ballet, arthritis and suffering from anorexia during his younger years.
He previously said: "I had worn out both hip joints from dancing and ballet, and it was made worse by the fact that I have arthritis. My mother suffers from rheumatoid arthritis but I have osteoarthritis.
"Ironically, I am the patron of the National Osteoporosis Society which is all about keeping bones healthy. I had put my body through an enormous amount of stress and strain. I was also anorexic when I was younger, which didn't help, because it causes malnutrition of the bones, coupled with the dancing, which makes it worse."
A spokesman for Craig said: "No date has yet been set for his operation."
In 2015, Craig's fellow judge Darcey Bussell underwent hip surgery despite previously saying she was hoping to avoid it by taking supplements.
Speaking in 2007, she said: "Damage to the hip joints is progressive, but with a good diet, supplements such as glucosamine (which reduces inflammation) and chondroitin (which slows cartilage breakdown), plus gentle exercise, I just pray I will be able to avoid the surgery.
"Even when I think of the pain I have endured and the degradation of my hips, I can't say I regret dancing. It's been a joy for me."