The 37-year-old opted for a black trouser suit by Altazurra, patent heels and a Stella McCartney Falabella clutch for the occasion, choosing a hairdo reminiscent of her wedding hair - the low bun with loose strands framing her face. Meghan went the classic route with a crisply tailored black pantsuit from designer Altuzarra.
Celebrity stylist and PR Rochelle White told Femail: 'Megan has been mindful this evening in regards to her outfit. The woman knows how to wear one!
Harry also pulled amusing faces when interacting and meeting other children at the event.
'I think she is aware that wearing a sexy dress, wouldn't have been appropriate for the audience and ceremony.
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At the end of the event, Harry and Meghan met the children's choir from Riverside School, for pupils with special needs, based in St Mary Cray, Orpington, which won an award.
Since her marriage to Prince Harry back in May, there has been a keen eye on Markle's fashion choices.
Harry also made a "pinky pledge" with Matilda during a reception before the awards ceremony began, hooking his little finger around the girl's finger.
Winners included four-year-old Mckenzie Brackley, four, who had to learn to speak, swallow, eat and drink and move again due to acute flaccid paralysis.