The royal was photographed mingling with others outside the Church of St. Mary the Virgin in Frensham, shortly before the wedding kicked off.
She looked regal in a pleated navy shirt dress that she paired with a stand-out Philip Treacy fascinator and Aquazzura pumps.
Meghan Markle is planning to reunite with her dad in the USA later this month, according to her friends.More news: IAG's Aer Lingus profits soar but Vueling losses deepen
The brand, of course, was thrilled: there's no better publicity for a fashion label than for the Duchess of Sussex to wear your clothing.
Anyway, we mustn't forget that it was her birthday.
Now she's taken to Twitter to accuse Meghan of neglecting their father - by refusing to send him a birthday card.
Thomas reportedly suffered a heart attack after he was caught staging paparazzi photos before the wedding.
The tweet came after Samantha had joked about her sister and Prince Harry's intention of retreating from the media - calling Meghan Cruella DeVil.More news: Ryanair proposes mediator for Irish pilots union talks
Prince Harry and Meghan Markle leave St George's Chapel at Windsor Castle after their wedding in Windsor, May 19, 2018.
The is not the first time the half-sister has attacked Duchess Meghan, as last month she tweeted, "How about you pay tribute to your own father?!"
While at a royal engagement with Harry in Belfast, Northern Ireland, in March, Meghan gave a hint of what the future may hold for the young couple when they met a husband and wife team who make baby products.
Listen, I'm sure there were more personal and private message to Duchess Meghan, but I'll take what I can get.More news: BlackBerry launches 'Make in India' phones
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