Celine Dion has a seizure onscreen in documentary's unfiltered view of stiff-person syndrome

The dichotomy of Celine Dion’s life is made clear almost immediately.

In “I Am: Celine Dion,” she’s standing onstage, the mania surrounding her every performance in full effect as she plows through Ike and Tina Turner’s “River Deep – Mountain High” in a voice like a tsunami.

In the next scene, she’s in a fetal position being strapped to a gurney by medics.

It’s a jarring juxtaposition, but a necessary one.

Dion’s life is laid bare in the truest sense in the new documentary directed by Irene Taylor (the Peabody Award-winning “Hear and Now” and Emmy-nominated “Beware the Slenderman” among her ouvere).

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In the 100-minute film, the global superstar is usually sans makeup, her hair pulled back into a tight bun. She might be in her gorgeous Las Vegas compound in pajamas and bare feet one moment and, in another, she’s slowly putting on thick socks as she awaits a needle in her vein for a plasma exchange treatment.

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Often, she is crying, both in frustration of how the extremely rare neurological disorder stiff person syndrome has held her voice and body hostage and also out of sadness from being robbed of her true joy: singing and performing.

The film, which plays in theaters nationwide starting June 21 and comes to Prime Video June 25, is affecting and raw – the latter not usually one associated with a diva of Dion’s renown.

But “I Am: Celine Dion” offers a portrait of a woman whose kindness is genuine, as Taylor confirms, and her fortitude commendable. It also showcases her family life now (with 13-year-old sons Nelson and Eddy at home), offers intimate footage of late husband René Angélil cutting the umbilical cord of their first born, René-Charles, now 23, as well as plenty of iconic performance clips that cement her legacy.

“I did not make the film to generate sympathy for her,” Taylor tells USA TODAY. “But it was impossible not to feel for this person.”

Celine Dion suffers an episode of stiff person syndrome on camera

The most harrowing scene in the documentary – and one certain to provoke tears – sneaks up toward the end and plays out in real time.

Last year, after two days of battling with her voice in a recording studio – her first time trying to sing in two years – Dion finally reached a level of satisfaction. Her euphoria, however, triggered the violent muscle spasms that accompany SPS.

About 10 minutes after going into a nearby room to do routine stretching exercises with her physical therapist, spasms froze her body in what her therapist referred to as a seizure.

Dion’s security guard was called in to assist in turning her clenched body on its side as she lay motionless with fingers curled, eyes wide and unblinking and lips involuntarily twitching rapidly. She couldn’t speak, but moaned in obvious agony and was administered medical nasal spray to relax her contracted muscles.

Taylor happened to be filming with her cinematographer Nick Midwig, and says there was never a discussion not to include the visceral scene in the film.

 “We were just trying to figure out what was happening,” Taylor says. “And as Celine likes to say, ‘do not flinch.’ And we did not flinch. We knew enough to shoot now and talk about it later … but there was never a question of whether or not we would include it. I did not show the film to Celine until it was done and the first thing she said to me was, ‘I think this film will help me’ and after a pause, ‘Don’t cut anything away from that scene.’ I think she felt validated and said, ‘Now people will understand.’”

The authentic kindness of Celine Dion: ‘It’s really notable’

Dion has always carried a vibe of a lovable kook. She can be silly and overdramatic and rarely gets through a sentence without breaking into song.

She's also, as shown in subtle ways, unfailingly kind, whether it be her driver, a sick employee, her band members or her treasured Labrador, Bear (who is frequently seen faithfully laying mere inches from Dion and whose memory the film is dedicated to).

As Taylor says, the year-plus of filming with Dion made her realize “the pressure of being ‘Celine Dion.’

“One of the first things I noticed about her is that her kindness is really notable. Like so many people her status, Celine really can’t have a normal life,” Taylor says. “And I think the kindness comes from this place that she’s grateful that she has an inner circle and some normalcy.”

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Why Celine Dion will never give up

It’s easy for an observer to conclude, why not just tend to your health and retire? Dion has the financial stability from a lifetime of work and a stunning home with her preteen sons who clearly love spending time with their mom.

But this is someone whose life has been synonymous with public adulation and speculation. You hear in her voice the genuine heartbreak as she recalls canceling shows with vague excuses (sinus and ear infections the most popular go-to) and her determination to return. She also recounts, stoically, her past reliance on Valium, and how she would take dangerous amounts of up to 90 milligrams a day to alleviate her vocal spasms.

But as Dion continues to regain her singing ability, the cloud is lifting.

“I think her voice brings her joy and if you look at singing traditions throughout history, singing is yoga,” Taylor says. “It’s a way to for people to find happiness and laughter and she just happened to have spectacular pipes. I have a deaf mother who used to sing to me as a baby and she didn’t hit the notes, but it imprinted on me that music is a gesture of happiness and love, and for (Celine), she wants to sing.”

Dion remarks at one point in the film, “My voice has been the conductor of my life.” But later she makes a promise that exemplifies her continued desire to get back on stage: “If I can’t run, I’ll walk. If I can’t walk, I’ll crawl. But I won’t stop.”