When Shania Twain fell ill with a "mysterious" sickness that weakened her singing voice in the mid-2000s, she was sadly forced to retire from showbiz — and feared she'd never be able to perform again.

“It was very depressing for me. I really believed that I would never sing again. I was convinced, because for a long time I just couldn't get [sound] out. It wasn't my vocal cords, which was very frustrating [because] if it was a straight-ahead problem I could just have an operation for, then I would have done it and dealt with it and got back to singing. But it was so much more mysterious than that," the 49-year-old star revealed in a new interview.

shania twain

Shania performing at the Super Bowl in 2003.

The mom-of-one was later diagnosed with dysphonia, an impairment in the ability to produce sounds with the body's vocal organs. After receiving treatment and undergoing rehab, Shania returned to the stage in 2012 — her first concert tour in 11 years — with her 'Shania: Still the One' Las Vegas residency.

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“[Recovering from this illness] was a slow, painful process. It was like learning to walk all over again. I had to learn how to use [my vocal] tools from scratch," she told Entertainment Weekly.

shania twain

Shania performing in July 2014.

Now, the "Man! I Feel Like a Woman" songstress is gearing up to embark on her farewell tour. The country superstar's 'Rock This Country' concert series is set to kick off in Seattle on June 5 and will include 48 cities throughout the US and Canada.