Tennis star Serena Williams has served up wedding advice to her friend, royal bride-to-be Meghan Markle.

Williams is an expert on over-the-top nuptials – her November wedding to Reddit founder Alexis Ohanian, 35, featured a Beauty and the Beast theme, three dresses and a carousel – but her tip to Meghan was simple.

“I just think it’s so important to enjoy the moment,” Williams, 36, said on Good Morning America on Friday (Thursday US time).

“If I could give her any advice it would just be to enjoy the preparation and enjoy the planning. It just goes so fast.”

Added Williams, “And eat the cake. I didn’t get to eat mine at the wedding. We were just having so much fun!”

The former world number one has said she’s “super happy” for Meghan, describing her as “incredibly nice”.

Williams was coy when asked on Good Morning America if she’ll be at St George’s Chapel at Windsor Castle with 599 other guests when Meghan, 36, weds Prince Harry, 33, on May 19.

“I don’t know,” she said.

“We’ll see if I can make it. Don’t be asking me them questions!”

Williams clicked with Meghan when they met in February 2014 when playing in a celebrity beach football game.

The then-actress talked about their instant and strong connection on her now-defunct lifestyle blog The Tig.

“We hit it off immediately, taking pictures, laughing and chatting—not about tennis or acting, but about good old-fashioned girly stuff,” Meghan wrote, according to ET.

“She quickly became a confidante I would text when I was travelling, the friend I would rally around for her tennis matches, and the down-to-earth chick I was able to grab lunch with.”

While Meghan might be grateful to Williams for her big day advice, she has her own experience to fall back on when it comes to weddings.

In 2011 she wed producer Trevor Engelson, 41, in the Caribbean in a wedding weekend that featured beach wheelbarrow races. The photos outlived the two-year marriage.

Meghan also has a screen wedding under her belt. On April 25 her Suits character Rachel Zane exchanged vows with TV husband Mike Ross (played by Patrick J Adams) in Meghan’s final episode on the legal drama.

The pair wed to the tune of John Legend’s All of Me before both characters were written out of the show.

Meghan’s vows as Rachel were more informal than they are likely to be at Windsor Castle: “I know that I fought it at first, but now, Mike, I can’t imagine living alongside anyone else for the rest of my life.”

She’s also likely to take her bridal style up a notch, although in the past she’s said her dream wedding dress would be slightly bohemian.

While her dress designer and style are top secret, one key detail confirmed is that she’s locked in Amal Clooney’s hairdresser for the day.

Celebrity stylist Miguel Perez, who charges $331 (£180 ) for a cut and blow dry at Chelsea’s Salon Sloane, was introduced to Meghan by Mrs Clooney, 40, who is said to be on the wedding guest list with husband George, 56.

“Yes, I do Meghan’s hair,” Mr Perez, whose signature style is sleek, voluminous waves, told The Mail on Sunday.

“We have talked about [the wedding] and we have a plan. I can’t say anymore but we know what we’re doing.”