The professional dancer, 41, was dripping with sweat after a gruelling workout at her dance studio.
Karen looked shattered as she slumped on the ground following hours in rehearsals.
The TV favourite wore a strappy grey sports bra and a pair of skintight matching leggings for the session.
Karen shared the snap and wrote: “Them: You having fun in rehearsals?
“Me: look at my face!”
It comes after Karen admitted that she would be heartbroken if an injury ever forced her to leave the BBC One dancing show.
Karen, who was forced out of the BBC show final last year after suffering a serious knee injury, said it was one of the “scariest” moments of her career.
The professional dancer, 41, said it was “catastrophic” to not be able to dance for two months during her recovery time.
Karen – who is the longest running female professional on the show – said she is thrilled to get back on the Strictly dancefloor later this year after allowing her knee to fully recover, but said she is now dealing with a back injury.
Speaking exclusively to The Sun, Karen said: “It really shocked me and really shook me up. With my knee injury I had a lot of physio and had a lot of digging to do.
“My knee is really good now, it’s just my back now.
“It took me out for two months and that for me was catastrophic.
“It was one of the scariest things that I’ve ever had to go through and the one thing that I didn’t want to get was surgery.
“Having that injury and not being able to be on the dancefloor, I took it as a reset.”
When asked if she every worries that an injury could stop her performing on Strictly in the future, Karen told us: “100 per cent, with this career you never know if one step or two steps ahead you’re going to twist an ankle.
“Not that I live in that fear but it’s always in the back of my head.
“But I would never retire from dancing – if I have two broken knees I would still go on the dancefloor.”
Karen will be back on the BBC One show for a 12th year running.
She said: “I am super excited to be returning – it will be my 12th year, I am the longest running female.
“I have no idea how that happened, it’s really incredible and I feel really lucky and grateful that they always ask me back which is nice, it’s my favourite time of the year.”
4
4