The 90-year-old legend, who became a global star in the film world with her roles in the likes of Mary Poppins and The Sound of Music, appeared in a video message shared on YouTube by the World Parkinson Coalition, as they addressed attendees at the event and commented that she knows "well how devastating" the disease can be.
She said in the clip: "Good evening, everyone, I'm Julie Andrews and I'm pleased to welcome you to the seventh World Parkinson's Congress.
"Your participation is invaluable as we seek to find a cure to this terrible disease. I know well how devastating it can be.
"May we all become a beacon of light to stop it in its tracks. Count me in as a red thread. Thank you."
Dame Julie rose to worldwide fame with her Oscar-winning turn in Mary Poppins, before winning a Golden Globe award for her performance as Maria von Trapp in The Sound of Music.
In 2001, she left her mark on a whole new generation as Queen Clarisse Renaldi alongside Anne Hathaway in The Princess Diaries, before returning for the sequel three years later.
A third movie in the beloved series has been confirmed, but it's not yet known if she will reprise her role.
More recently, Dame Julie has earned herself an Emmy for Outstanding Character Voice-Over Performance for her role in Bridgerton as the narrator, Lady Whistledown.
Back in 2022, the veteran star revealed she hadn't actually met any of the cast of the Netflix show in person, despite featuring heavily with her narration.
She told Today show host Hoda Kotb: "You know I've never met the company in person.
"Of course, I see them on the show sometimes. But I do all my recording far, far away from them."
Dame Julie has daughter Emma Walton Hamilton, 63, with ex-husband Tony Walton, plus daughters Amy Leigh Edwards, 52, and Joanna Lynne Edwards, 48, with her late husband Blake Edwards.
She and Hamilton are set to collaborate on a reissue of their 2010 children's book The Great American Mousical, which gave the actress an outlet after throat surgery in 1997 meant she couldn't keep singing professionally.
Back in 2023, she told Forbes magazine: "I would go completely mad if I didn't have some lovely thing to work on.
"I think really, since I had a bad surgery on my throat, I've just turned to this with Emma and it's been such a joy.
"It has been very refreshing for me and reviving in a way, because of course, it was a very sad event."
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