Shania Twain regularly blacked out due to Lyme disease

Five-time Grammy winner Shania Twain said she feared falling off stage after being stricken by a tick in 2003 while horse riding.

Twain said: "My symptoms were quite scary because before I was diagnosed, I was on stage very dizzy. I was losing my balance, I was afraid I was gonna fall off the stage."

She was sick with the disease on her $87 million grossing, 113-date Up! tour and spoke of the illness in her new documentary 'Not Just a Girl', reports femalefirst.co.uk.

Twain added: "I was having these very, very, very millisecond blackouts, but regularly, every minute or every 30 seconds."

The singer's chronic sickness contributed to her developing voice disorder dysphonia, leading to throat surgeries and therapy.

She said: "My voice was never the same again. I thought I'd lost my voice forever. I thought that was it (and) I would never, ever sing again."

The singer's struggle also came as she was facing a divorce, reports femalefirst.co.uk.

She is getting ready to celebrate the 21st birthday of her son Eja D'Angelo in August, who she shares with five-time Grammy-winning producer Robert 'Mutt' Lange.