Strictly Come Dancing bosses are reportedly anxious that US singer Anastacia will not be able to continue with the show beyond this weekend.
The 48-year-old singer-songwriter and cancer survivor tore the scar tissue around her double mastectomy just before last weekend's programme.
This prompted a last-minute change to her dance routine.
She was left languishing in the bottom two after the public vote but was saved after the dance-off was scrapped, sending Melvin Odoom home after the first week.
— Anastacia (@AnastaciaMusic) 7 October 2016
Doctors have given her the go-ahead to continue but she is apparently still struggling.
Professional dancer Ian Waite, who has seen footage of the singer preparing with her partner Brendan Cole, told BBC Two's 'It Takes Two': "There is an issue.
"Anastacia's head keeps coming into Brendan whereas I would like to see her get her head out a bit more like a flower in a vase. Maybe it's because of her injury."
Anastacia is delighted she has been given the green light to keep dancing as she is donating her appearance fee to Cancer Research UK.
A spokeswoman recently said: "She is doing this to raise money for breast cancer, so unless a doctor tells her she can't carry on, quitting would never be an option.
"Anastacia and Brendan are now in rehearsal. Anastacia visited the clinic of a specialist in breast reconstruction surgery."
She continued: "The doctor again confirmed that there was a tear in the scar tissue, which although painful is not permanent.
"She was given the all clear to dance this weekend with the caveat that the routine is carefully choreographed and she has been given the appropriate medication.
"Brendan was with her for her appointments and they have been filmed for this weekend's episode."