The former 'Corrie' star may be forced to pull out after she slipped a disc on Tuesday whilst practising her quickstep routine with partner Artem Chigvintsev.
The actress had an MRI scan yesterday so docs can assess the damage and is also taking painkillers and been told to rest.
A source told The Sun: “Natalie is fearing the worst and would hate not to be able to perform. It is touch and go.”
Natalie and Artem were due to dance to 'Yeah!' by Usher as part of the show’s 'Mixtape' themed night.
Natalie and dance partner Artem Chigvintsev performing on last week's 'Strictly'
It's not the first time Natalie has been injured during training.
Last month she was forced to see a physio after damaging her knee ahead of the first live show after putting in a gruelling six hours of rehearsals each day.