The 37-year-old royal - who was known as Meghan Markle and was an actress in 'Suits' before marrying Prince Harry in May this year - shared in August 2017 that she had begun her acting career because of Julia.
And after being made aware of the fact during an interview with People magazine this week, 51-year-old Julia is over the moon to learn she has a royal fan.
She told the publication: "It's a great night for me! But I am just going to be floating on that all night!"
In the 2017 profile for Glamour magazine, Meghan - who is currently expecting her first child with her 34-year-old spouse - was tasked with listing the 10 women who "changed her life", and she noted the 'Notting Hill' star with being the actress who made her want to follow that career path.
She wrote at the time: "She was the first person I saw onscreen and thought, 'That looks like so much fun; I wanna do that.' When I was younger, someone once told me, 'You kind of look like Julia Roberts in profile.' It was the best compliment of all time."
The news comes after Julia recently insisted she wouldn't call herself a "film actor" because she's just interested in great roles, no matter what platform they might be on.
Speaking to BANG Showbiz, she said: "I mean, I've never called myself a film actor, I'm just an actor. I think for me, I go where the parts compel me and I don't know that a lot of creative people that would compartmentalise their places to be creative in that way.
"We're all just looking for the thing that we think we can bring something of value too it's not really the medium so much that is pursued."