The talk show icon and actress turned up to support the designer's new There She Grows initiative, which encouraged attendees at the stylish event to plant a tree in a bid to save endangered forests, and Oprah made her way behind the scenes after the show wrapped to surprise McCartney.
The shocked fashionista had no idea one of her personal heroines would be there and screamed with delight when she saw Winfrey, according to The Washington Post. The happy shrieks were audible over the noise of the backstage commotion, with the designer managing to utter out the words, "I'm dying" to her idol.
"It was beautiful. It was fun," Oprah smiled in response.
Winfrey explained to Women's Wear Daily she had flown into France especially to attend Stella's event, noting the There She Grows campaign is dear to her heart.
"I'm going to plant an oak because I already have hundreds of oaks in my yard. I'm a tree person," the "A Wrinkle in Time" star shared. "They represent the stability of life, the stillness of life, so I'm going to do one in honour of my mother."
Stella showcased 'upcycled' looks at her show and the sustainable line has also inspired race car champion Lewis Hamilton, another guest at the runway event, to save the planet with his new clothing line for Tommy Hilfiger.
"One of the things I'm incredibly inspired about by Stella is she's very much into sustainability," he said. "In my collection, I'm trying to catch up with her. My collection is 50 per cent recyclable and eco-friendly materials. The goal is, by the fourth collection, it's 100 per cent."