How Queen of tennis Serena prepared for royal wedding

'Do you like my necklace ... Do you like my braids?'

American tennis star Serena Williams rose early on Saturday to get ready for her friend Meghan Markle's wedding to Britain's Prince Harry with a gold face treatment mask and personal make-up artist.

Former world number one Williams, 36, posted videos on her Instagram account of herself and her partner Alexis Ohanian getting ready in their hotel room before heading to the ceremony at Windsor Castle.

"Hey y’all, so my friend's getting married today," she said as she filmed herself standing in front of the mirror in a towel.

"I've known her (Meghan) for so many years and I'm super happy for her."

Williams plans to play at the French Open later this month in a bid for her record 24th major championship. She returned to professional tennis in March after giving birth to her first child in September, although her coach has since said she has come back too soon.

Sitting on the hotel bed, Williams kissed and cuddled her baby daughter, named Alexis after her father, before putting on a gold facial treatment mask.

"I’m shaping my brows today, but not for you, just because I want to," she said, later adding that she was wearing her hair in braids.

"Do you like my necklace ... Do you like my braids?" she asked her partner. She said her chunky gold necklace was from the Heritage Collection by Italian luxury brand Bulgari.

By the time she was having her make-up applied, Williams said she was exhausted.

"I had this amazing energy but now I am incredible sleepy. I didn’t go to bed till three. I didn't go to bed till 3 a.m.," she said.

The tennis player teased her partner as he pulled up the trousers of his morning suit: "Are those high-waisted? This is not appropriate. This is uncool."

In her last video from her morning preparations, she and her partner were seen in full regalia before heading out to the ceremony.

"What's the verdict?" Williams asked, to which her partner replied, in a fake British accent: "Smashing. Where's my monocle?"