Heavily pregnant Meghan chose an elegant bespoke green coat decorated with black floral embellishments by Erdem, and Aquazzura Deneuve Black Bow Pointy Toe Pumps.
Canadian-born, London-based designer Erdem Moralioglu counts the Duchess of Cambridge, former US first lady Michelle Obama, style doyenne Alexa Chung and actress Keira Knightley among his clients.
The Duke and Duchess of Sussex were meeting young Canadians in London who are forging ahead in the fields of fashion, tech entrepreneurship, business and the arts.
Former actress Meghan lived in Toronto for several years while filming Suits.
Meghan’s super-slim stilettos featured a black bow tied at the back.
Her attentive husband Harry held out his hand to guide his pregnant wife as she arrived at the engagement.
Erdem was tipped to design Meghan’s wedding dress, but in the end the duchess wore a pure white boat neck wedding gown by Clare Waight Keller for Givenchy.
Meghan’s accessories at the Commonwealth event included a black Givenchy satin clutch.
But she went without her diamond engagement ring, wearing only her wedding band.
Pregnant women sometimes have to remove their rings if their hands swell in their final trimester.
But Meghan’s engagement ring actually appeared to be loose when she appeared on stage at WE Day UK with Harry last week, with the diamond facing the wrong way round as she waved at the audience.
Meghan’s ring, designed by Harry, was made using two diamonds from Diana, Princess of Wales’s personal collection and a central diamond sourced from Botswana.
It is estimated to be worth more than £120,000 ($223,265 AUD).
Later, Meghan switched outfits for the Commonwealth Day service at Westminster Abbey.
She was dressed in an all-white ensemble, complete with a chain-print Victoria Beckham dress, and a white pillbox hat, with Victoria Beckham satin pumps in green and coordinating green clutch bag.
WATCH: Meghan and Harry leave Commonwealth Day service at London's Westminster Abbey
Kate, who was among the senior royals attending the annual event, wore a red Catherine Walker coat and matching dress.
It was the same outfit she wore for her arrival in New Zealand in 2014 but with a slightly different style hat.