The 57-year-old sang her hit 2002 song "I'm Alive" in the campaign video, as dancers around her applied makeup and held the brand's products aloft. "I'm honored to join my dear friend Charlotte for this magical holiday campaign," she exclaimed. Céline has come a long way in the past year, after being diagnosed with Stiff Person Syndrome in December 2022. Céline opened up further about working with Charlotte on the holiday campaign, explaining that the move made perfect sense given their close friendship. © Getty Images Céline was diagnosed with Stiff Person Syndrome in 2022Stiff Person Syndrome is a progressive neurological disorder that manifests in symptoms like stiffness of the limbs, heightened sensitivity, painful muscle spasms, and difficulty walking.