Actor-turned-duchess Meghan Markle always sets aside time from her royal duties to cheer on one of her most beloved friends: tennis champion Serena Williams.

When Serena Williams takes the court at Grand Slam tournaments around the globe, all eyes aren’t just on her—they’re also on her cheering section. Duchess of Sussex Meghan Markle has traveled the globe to support her longtime friend at some of her biggest matches, including the U.S. Open in New York City, the Australian Open in Melbourne and Wimbledon outside of London.

But it was another sport that brought Williams and Markle together: football.

In early 2010, Markle had yet to star on her breakthrough role in the USA network TV show Suits when she had a chance meeting with the already established global phenom Williams at the Super Bowl in Miami. Four years later, they teamed up to put their flag football skills to the test at the 2014 DirecTV Beach Bowl, in New York City. (Their team won.)

"We hit it off immediately, taking pictures... and chatting not about tennis or acting, but about all the good old fashioned girly stuff," Meghan wrote on her lifestyle blog, The Tig (which she shut down in April 2017).

Later that year, Markle was by her friend’s side through some of her biggest career moments as Williams won the 2014 U.S. Open and 2015 Australian Open. Markle shared her joy on her now-deleted social media channels. "So happy for you @serenawilliams!! I was juuuust hugging you for your win at #usopen. Now @AustralianOpen! #onfire" she Tweeted in January 2015.

Markle was also spotted at Wimbledon in 2016, which was around the time she was set up on a blind date with Prince Harry.

Serena Williams and her husband, Alexis Ohanian, arrive for the wedding ceremony of Britain's Prince Harry, Duke of Sussex and actress Meghan Markle at St George's Chapel.

Serena Williams and her husband, Alexis Ohanian, arrive for the wedding ceremony of Britain's Prince Harry, Duke of Sussex and actress Meghan Markle at St George's Chapel.

Sports hasn’t been their only common ground. The duo were seen together at New York Fashion Week in September 2016 and Williams was famously one of the VIP guests at Markle’s royal wedding to Prince Harry in May 2018. Just like any other BFF, she posted Instagram videos of Markle’s big day. “Hey y’all, so my friend’s getting married today,” she said in a clip. “I’ve known her for so many years and I’m super happy for her.”

The friends (both born in 1981) have also been known to rave publicly about one another. “Her personality just shines,” Williams told Vanity Fair in 2017, adding that she also gave Markle advice about life in the spotlight. “I told her, ‘You’ve got to be who you are, Meghan. You can’t hide.’”

Even though the royal now lives in Windsor, England, while the athlete is based in Palm Beach Gardens, Florida, the friends still lean on each other in challenging times. After Williams’ controversial court behavior at the 2018 U.S. Open, the tennis player told Australia’s The Sunday Project that she and Markle “have known each other for a long time, but we really kind of are relying on each other right a lot recently. We were actually just texting each other this morning.”

Kate Middleton (left) and Meghan Markle attend day 12 of the Wimbledon Tennis Championships at the All England Lawn Tennis and Croquet Club on July 14, 2018 in London, England.

Kate Middleton (left) and Meghan Markle attend day 12 of the Wimbledon Tennis Championships at the All England Lawn Tennis and Croquet Club on July 14, 2018 in London, England.

A few weeks later, Williams praised her friend’s cookbook, Together: Our Community Cookbook, saying: “I used to call you Meghan (and I still do) but dear Duchess of Sussex your first project ‘Together’ a cookbook bringing women of all cultures together. I could not be more excited about it and proud of you. It’s beautiful—diversity, inclusivity, coming together in grief or joy.”

Often, with both of their megastar statuses, even the smallest actions can elicit huge headline-grabbing stories. For example, when Markle wore jeans while attending Wimbledon on July 4, 2019 to support Williams, she drew criticism from traditionalists who considered it disrespectful. (She was sitting in an area reserved for members of the All England Club, which maintains a dress code.)

Williams then used her post-match press conference time, which is usually dedicated to debriefing on the match, to set the record straight. “I didn’t know there was negative media out there,” she said from the All England Lawn Tennis and Croquet Club

"Any time I see her name attached to anything, I don’t read it. She couldn’t be a better friend to me. Low moments, high moments, she’s always there, and that’s all I want to be to her.”