The 34-year-old singer and her professional partner Brendan Cole were perfecting their moves for a Charleston ahead of Saturday night's show, when a daring move went wrong and Sophie was dropped on her head.
Now bumped and bruised, the star has said the accident has made her nervous about performing the high-energy routine.
"I had to lie down in a dark room afterwards. I am so scared of it, but I know we should just do it… I don't want to be frightened of it," she said.
"The routine that we are working on is pretty high energy, quite a work out. I have got some impressive bruises and I end the routine out of puff. When I first fell on my head, my confidence was really dented."
Professional dancer Brendan, who has appeared on Strictly since it began in 2004, has never performed a Charleston in the four years since it was introduced.
"Previously I've always avoided it; it's not really my bag" he admitted. "I can do it, and I have actually really enjoyed putting the choreography together.
"One of the tricks in particular, I lay back and flip Sophie over my head, and unfortunately in rehearsals she actually landed on her head - first fear was, 'Are you alright?'
"It is a very ambitious routine, I don't believe in doing the minimum but the maximum. I say push her and see what happens."
Despite her unexpected tumble, Sophie has bounced back. Earlier in the week, she told fans, "Bumped my head training yesterday. I just checked - still know the raps in Shoop and Let's Get Ready To Rumble so all vital cells in tact."
Later that same day, the mum-of-three tweeted, "Just danced our new routine at home. Sonny rolled his eyes and said 'ah mummy, you're trapped in strictly world again'."