The Grand Slam champion was seen at the event in Miami on Friday, giggling and gossiping with the Duchess on the sidelines of the Sentebale Polo Cup.

The 42-year-old was wearing a stunning white skirt and black top combo, as she embraced Prince Harry – having grown close to the couple since they began dating.

The highly anticipated match is held every year in aid of Sentebale, the charity Harry co-founded in 2006 that supports young people and children living in southern Africa.

The Grand Slam champion was seen at the event in Miami on Friday, giggling and gossiping with the Duchess on the sidelines of the Sentebale Polo Cup

The 42-year-old was wearing a stunning white skirt and black top combo, as she embraced Prince Harry – having grown close to the couple since they began dating

Meghan Markle and Serena Williams (pictured in 2014) first met at a Super Bowl party in 2010 and eventually became close friends

The Duke captained the Royal Salute Sentebale team against the Grand Champions, led by his good friend Argentinian polo player Nacho Figueras.

READ MORE: Meghan Markle plants passionate kiss on Prince Harry as she presents him with trophy after he WON glamorous charity polo match in Miami – with Netflix cameras there to capture every minute of the action

Meghan Markle and Serena Williams first met at a Super Bowl party in 2010 and eventually became close friends.

The Duchess of Sussex and the American tennis champ chatted to one another on the royal’s first Archetypes podcast on Spotify about the double standards women face when they are labelled ‘ambitious’.

Serena, who has now retired from tennis explained during the first episode of the series that she is ‘super loyal, to a fault’ after being ‘friends for so long’ with the Duchess.

They claimed they had their first ‘real hangout’ in 2014 at the DirecTV Beach Bowl, although they briefly crossed paths in 2010 at the SuperBowl.

Meghan, who was starring on Suits at the time, wrote on her now defunct blog The Tig: ‘We hit it off immediately, taking pictures, laughing through the flag football game we were both playing in, and chatting not about tennis or acting, but about all the good old fashioned girlie stuff. So began our friendship’.

According to Mark Hodgkinson in Serena: A Graphic Biography of the Greatest Tennis Champion, the women’s friendship quickly evolved through frequent phone calls and texts.

Entitled ‘The Misconception of Ambition with Serena Williams’, the Duchess of Sussex spoke to the tennis star in the podcast

The Duchess of Sussex, 41, and the American tennis champ (pictured with husband Alexis Ohanian at Meghan’s wedding to Prince Harry) , 40, chat to one another on the royal’s first Archetypes podcast, released on Spotify today, about the double standards women face when they are labelled ‘ambitious’

Williams was in attendance for Markle’s blowout baby shower in New York City in February 2019, a few months before she gave birth to son Archie with her husband Prince Harry

After becoming Prince Harry’s girlfriend and then a Duchess, Markle leaned on Serena for mentoring on how to handle the paparazzi and the international media.

Serena advised her to ‘stop being so nice’, according to the author.

And when Meghan learned she was pregnant shortly after Serena’s little girl was born, Serena offered her parenting advice.

Last year, Williams revealed: ‘We have known each other for a long time, but we really are relying on each other a lot recently.’

She added that watching Meghan marry Prince Harry in May 2018 was particularly special.

Serena was one o the first people to defend Meghan following a backlash after her bombshell interview with Oprah Winfrey.

In a statement on Twitter after the interview aired, Williams described her as a ‘selfless friend’ who ‘teaches me every day what it means to be truly noble’.

‘Her words illustrate the pain and cruelty she’s experienced,’ Williams wrote.

‘I know first hand the sexism and racism institutions and the media use to vilify women and people of color to minimize us, to break us down and demonize us. We must recognize our obligation to decry malicious, unfounded gossip and tabloid journalism.

‘The mental health consequences of systemic oppression and victimization are devastating, isolating and all too often lethal.

‘I want Meghan’s daughter, my daughter and your daughter to live in a society that is driven by respect.

‘Keep in your memory the fruitage of the spirit is love, joy, peace, long-suffering, kindness, goodness, faith, mildness, self-control. Against such things there is no law.’