Jon Kelf ran five marathons before he was diagnosed with Stiff Person Syndrome (SPS) - the incredibly rare, incurable neurological disorder in 2019.

SPS causes the body and limbs to stiffen and is often triggered by emotional stress or noise.

Jon Kelf lives with Stiff Person Syndrome (SPS) (Image: Jon Kelf / SWNS)

The 56-year-old can now “barely walk” and has been forced to quit his job as an electrical engineer, instead spending his time taking photos and gardening.

Dion, 58, was diagnosed with SPS in December 2022, but recently announced she would return to performing with 10 shows at the Paris La Défense Arena over five weeks, beginning on September 12.

Mr Kelf, who lives near Barton Broad in Norfolk, said she might struggle to get back on stage.

“I don’t know if she has bad days like me, but it may get cancelled if she does," he said.

Before he was diagnosed, Jon Kelf ran five marathons (Image: Jon Kelf / SWNS)

“It’s mainly crowds, situations where it’s chaotic when my symptoms are worst, so I stay away from them.

"It’ll be a lot for her to do so many shows on the trot."

He added that he fears the tour could impact the way SPS is viewed by the general public.

“I think it could undermine how seriously people take us, other sufferers," Mr Kelf explained.

Celine Dion has announced 10 shows over five weeks (Image: AP / PA Images)

“Like any illness, some can carry on doing their job, other people like me can’t. The illness is not the same for everyone.

“I’m positive that she’s doing the tour, it’s inspiring, but it would be nice if more could come out of it for other sufferers, otherwise people may look at her and think, ' Why aren’t they doing more? ' so it could work negatively.

“My message to her would be to think of other sufferers. If you can do anything to help or give hope to them, that would be great.

“She could be a bit more helpful to the community, because I know several feel she’s done very little."

© Eastern Daily Press