In the clip, which was shared on her Archewell Foundation's website, Markle said she wanted to use the occasion to encourage others to contribute 40 minutes of their time to an act of service, specifically to help women reentering the workforce amid the COVID-19 pandemic.
"Because I'm turning 40, I'm asking 40 friends to donate 40 minutes of their time to help mentor a woman who's mobilizing into the workforce," Markle explained in the video. "Over two million women in the U.S. alone and tens of millions around the world have lost their jobs due to COVID."
She added, "I think if we all do it and all commit 40 minutes to some act of service, we can create a ripple effect."
Markle quickly received a lot of celebrity support, including a prominent member of the royal family -- Princess Eugenie. Eugenie posted about the initiative on her Instagram Stories on Thursday, writing, "To celebrate dear Meghan's 40th birthday I'm contributing 40 minutes of mentorship to support women reentering the workforce."
Eugenie, who is the cousin of Markle's husband, Prince Harry, also shared a cute "Happy Birthday" GIF and promoted the initiative with some of the same information Markle shared in her video. Eugenie is currently living in the duke and duchess' former Frogmore cottage home in Windsor, England, with her husband, Jack Brooksbank, and their 5-month-old son, August.
Other stars who publicly supported Markle's 40X40 program included Hillary Clinton, who posted about it on Instagram, writing, "Meghan, The Duchess of Sussex, turns 40 today. To help celebrate, please join me in committing 40 minutes today to community service. When everyone contributes a little, a lot can change for the better. #40x40 #CompassionInAction."
According to People, Markle's office also confirmed that Adele, Amanda Gorman, Amanda Nguyen, Ibram X. Kendi, Gloria Steinem, José Andrés, Dr. Nadine Burke Harris, Sophie Grégoire Trudeau, Oscar de la Renta's creative director Fernando Garcia and Stella McCartney have all committed their time to the cause.