The news of Meghan's pregnancy had sparked fears among royal watchers about exposure to Zika virus, which is officially listed as a risk in Fiji and Tonga.
Meghan was pictured in the cape dress and wearing dazzling diamonds as she joined Harry at the Grand Pacific Hotel to attend the state dinner hosted by the Fijian President.
The royals have been touring Australia for the Invictus Games, a multi-sport event founded by Harry for wounded ex-service personnel, which is now under way in Sydney.
Meghan Markle and Prince Harry are now on their royal tour of Australia, New Zealand, Tonga and, most recently, Fiji, where they found a touching way to pay homage to Queen Elizabeth II and her husband Prince Philip, whether they meant to or not.
Prince Harry and Meghan Markle have left Hervey Bay as they make their way to Fiji.
Meghan wore a dress by Australian label Zimmerman, a Stephen Jones hat, earrings which were a gift from the Queen and a bracelet given to her by the Prince of Wales.
Fiji, a former British colony, became independent in 1970 at a ceremony in the same Albert Park venue that was attended by Harry's father Prince Charles.
Kensington Palace says that though Meghan is not suffering from morning sickness, she was advised to skip the forest trip because of the bumpy trek there.
She and Harry were met at Suva's Nausori Airport by Melanie Hopkins, the High Commissioner and chief of protocol, Jonetani Tagivetaua.
The Queen and Prince Philip arrive in Fiji in 1953.
A video posted online showed a well-wisher calling out: "Congratulations, I hope it's a girl!" to which he replied "So do I!"
The first half of the Duke and Duchess of Sussex's royal tour of Australia and New Zealand got off to a stylish start.
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