The 38-year-old cited “personal reasons” for abruptly leaving the BBC dance show in October last year.
At the time, it was rumoured he had left following an on-air spat with head judge Len Goodman.
But in an interview with Bryony Gordon’s Mad World podcast, the ‘Pop Idol’ star said his PTSD had got so bad that he considered breaking his own leg in a bid to leave ‘Strictly’.
He said: “I was really ill. I was dragging myself to rehearsals. I just couldn’t do it any more. It was so bad I thought - I’m not joking - I thought about breaking my leg.
“I decided to take on Strictly because I bloody love dancing. And I bloody hated it, because I was so ill.”
The ‘Leave Right Now’ singer revealed he has spent £500,000 on treatment over the course of his adult life, including seeing a shaman and doing ‘shaking therapy’.
He explained: “Animals, if they get attacked and survive, will shake and shake off the trauma. So in my therapy I’ve done a lot of shaking.
“I’ve probably spent at least half a million quid on my therapy. I’ve spent at least £200,000 on treatment alone. I could afford it - most people can’t. It makes me desperately sad.”
In a separate interview with the Times at the weekend, Will insisted he didn’t leave because of any differences with Len Goodman.
He said: “It was important for me to leave Strictly for my own wellbeing. It was a number of things. It was nothing to do with the people on the show, and it certainly wasn’t because Len Goodman dissed my salsa – I mean, come on!”
Useful websites and helplines:
Mind, open Monday to Friday, 9am-6pm on 0300 123 3393 Samaritans offers a listening service which is open 24 hours a day, on 116 123 (UK and ROI - this number is FREE to call and will not appear on your phone bill.) Get Connected is a free advice service for people under 25. Call 0808 808 4994 or email: email@example.com