She will receive $US2 million ($A3 million) for just one song.
The 56-year-old My Heart Will Go On singer was forced to stop performing following her 2022 diagnosis of the rare condition Stiff Person Syndrome, but is set to make a return to the stage for just one song at the event in France.
TMZ has reported - after she was spotted checking into the Royal Monceau Hotel in Paris on Monday: "Sources with direct knowledge tell us she is getting ready to take the stage Friday.
"Our sources say she will be paid handsomely ... $2 million!!!
"By the way, that's for just ONE song!"
The outlet added an insider had insisted she is "feeling fine" amid her health fight.
Dion's apparent plan to perform comes after she shared footage of her suffering a torturous seven-minute seizure caused by her Stiff Person Syndrome.
The astonishingly vulnerable video of her fit was included in her new documentary I Am: Celine Dion, which details her battle with the condition.
It showed the singer's doctor conducting an evaluation as she had been experiencing spasms due to SPS, with sports medicine therapist Terrill Lobo saying: "Part of the disease is that as soon as you go into a contraction, sometimes… the signal to release it, doesn't understand, so it ends up just staying in a contracted position."
After he gets Dion to lie down on a massage table, the singer keeps spasming, which Lobo warns could spark "a crisis".
The Grammy-winning entertainer is then seen going into a severe, full-blown fit as the doctor calls in another member of his medical team to bring in Valium.
Dion can be heard moaning in agony as she shakes while face down, and when Lobo goes to lift her on her side the singer starts whimpering and crying.
One more shocking moment in the scene shows Dion wide-eyed and unable to move on her own but still conscious.
She then starts crying as the spasm continues to wrack her body and when Lobo asks her to try and "calm down", the singer starts sobbing more loudly.
Dion is seen getting two doses of a nasal spray before she eventually starts to come out of the seizure.
Lobo says if she hadn't recovered she would have had to have been rushed to hospital.
Dion says after she recovers the incidents make her feel "so embarrassed".
She adds: "I don't know how to express it, like, it's just, you know, like, to not have control of yourself?"
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