It was to celebrate the 50th anniversary of the investiture of Prince Charles, her father-in-law.
The Duchess of Sussex made a surprise appearance with Prince Harry in London on Wednesday at an event, which celebrates young people all around the United Kingdom who have made a difference to their community.
Former actress Meghan, dressed in a blue blazer, black top showing off her large bump, and black pants, held Harry's hand as they moved centre stage at the SSE Arena in Wembley, London.
He said: "If we look at the world we're living in, I know it can feel challenging sometimes, but your role is to shine the light".
Markle, meanwhile, looked gorgeous in a gold and silver brocade dress which featured foil floral print.
A party at the Buckingham Palace proved to be an ice-breaker between the Duchess of Cambridge and the Duchess of Sussex, according to a report in news.com.au.
She carried a pale pink clutch in her hands and wore suede stiletto heels in the same shade, while she swept her glossy dark hair back into a chic chignon.
The Duchess showed off her blossoming baby bump in a tight black top teamed with a blue blazer and skinny jeans.
Prince Harry gave a powerful speech, which mainly focused on encouraging the young audience to become more involved in creating positive change.