Celine Dion took near-fatal dose of Valium for spasms

Dion has now revealed she relied on the sedative drug Valium to control her pain but ended up taking high doses that were not safe.

She told People magazine the first time she felt a muscle spasm was when she was on tour in Germany, which led her to use medicine in a bid to resolve it. 

"I had breakfast, and I suddenly started to feel a spasm," she said.

"My vocal exercise made it worse ... 

"We started with two milligrams (of Valium) to see if it would help, and then 2.5 and then three and 15 and 50 (and later 90 milligrams to get through a performance)."

Dion said "it could have been fatal". 

"I did not question the level because I don't know medicine," she said.

"I thought it was going to be OK. 

"It worked for a few days, for a few weeks, and then it doesn't work anymore. 

"I did not understand that I could have gone to bed and stopped breathing. 

"And you learn - you learn through your mistakes."

Dion said of using the drug: "It's very important to know ... people who know me well enough, they know that I did not take medicine just to drug myself, just to be high or to be stoned."

Dion said she had been "as professional as can be" throughout life.

"A disciplined, hard-working person doing what I need to do for my voice to be in top shape," she said.

After being diagnosed with the illness, Dion is now on a treatment plan that involves a combination of medicine, therapy and physical rehabilitation.

She said she hoped to be able to get back on stage to sing again.

Speaking in her feature-length documentary I Am: Celine Dion, the singer explained she "can't answer" whether she will be able to get back on stage. 

"I can't answer that … because for four years I've been saying to myself that I'm not going back, that I'm ready, that I'm not ready," she said.

"As things stand, I can't stand here and say to you: 'Yes, in four months'.

"I don't know ... my body will tell me. 

"On the other hand, I don't just want to wait."