It will mark the first joint engagement the Duchesses have carried out together, and royal watchers will be eager to see the sister-in-law's bond on display.
The palace announced on Thursday afternoon that Kate and Meghan will take to the royal box to watch the game.
It isn't just a leisurely visit for Markle and Middleton as they are set to actually meet with several former champions and speak with some ball boys and girls during their visit. Williams has not lost a Wimbledon final for 10 years, last defeated by someone who knows her better than most - her sister Venus. She finished off her look with na pair of nude heels.
Meghan and Kate have arrived at Wimbledon ready to cheer on their close friend Serena Williams in the Championships.
Unlike the Duchess of Sussex, the Duchess of Cambridge, or Kate Middleton, is likely to be a neutral observer (both officially and unofficially) as she does not have any personal connections with either Williams or Kerber.
Williams used to be the highest ranking female player but her seed plummeted to 25th after she left the sport to have her baby, Alexis Olympia Ohanian Jr.
"Every year, for a couple years, she comes out to Wimbledon, has supported me".
Trump in the UK: What now for the 'special relationship'?
Among them was Emily Bryce, who proudly carried a homemade banner written in Gaelic, in recognition of Trump's Highland roots. It goes with "Fake Schmooze", and says Trump has been "forced" into a climbdown to patch things up with Theresa May .
On Sunday, Kate and the Duke of Cambridge will watch the men's singles final on Centre Court.
'Now she's supporting me in a different role.
Ms Williams continued: "We have always supported each other, just been there for each other through a lot".
Williams admitted this time may be more hard, not least because she gave birth just 10 months ago, and has spoken about the tough delivery, which left her in hospital for six weeks. The Duchess of Cambridge's first engagement alone with the Queen wasn't until almost a year after her marriage to the Duke of Cambridge. Because of the length of the match, the second semi between Rafael Nadal and Novak Djokovic started late.
They played for six hours 35 minutes before Anderson triumphed 7-6 6-7 6-7 6-4 26-24.
She arrives in her 30th Grand Slam final - her 10th at Wimbledon on a 20-match winning run on the lawns of south-west London.
In fact, Djokovic was leading two sets to one before play was stopped for the night, and a no doubt tired crowd was sent to bed.