Meghan, Duchess of Sussex smiles during a visit to Tupou College in Tonga, Friday, Oct. 26, 2018. Prince Harry and his wife Meghan are on day 11 of their 16-day tour of Australia and the South Pacific. (AP Photo/Kirsty Wigglesworth, Pool)

Duchess Meghan has caused yet another dress to sell out in every size after wearing a beautiful blue outfit on the second day of her visit to Tonga with her husband Prince Harry on Friday (26.10.18)

The 37-year-old royal - who is expecting her first child with Harry, 34 - donned a $595 gorgeous sky blue shirt dress by American brand Veronica Beard from their ready-to-wear collection whilst attending the unveiling of The Queen's Commonwealth Canopy at Tupou College.

Britain's Meghan, Duchess of Sussex smiles during a visit to Tupou College in Tonga. (AP Photo/Kirsty Wigglesworth, pool)

Meghan teamed the 'Cary dress' with a pair of her go-to brand Aquazzura's baby-blue Amandine pumps and her hair in a low ponytail, and within hours of the tour images being shared online, the gown was no longer available to buy.

This isn't the first time the former 'Suits' actress - who was known as Meghan Markle before she married into the British royal family in May - has had websites crashing with fans eager to get their hands on the coveted pieces she's been pictured in, which has now been dubbed 'The Meghan effect'.

Britain's Meghan, Duchess of Sussex applauds during a visit to Tupou College in Tonga. (AP Photo/Kirsty Wigglesworth, pool)

Earlier this month, the duchess opted for a silk olive shirt by the Swedish brand when she and Harry visited Sussex on their first official visit to the county that features in their royal titles.

Meghan has attracted plenty of attention for her simple-but-chic looks on the tour of her 16-day tour of Australia, New Zealand, Tonga and Fiji and even wore a piece from her pal Serena Williams' fashion line. 

On the second day of her royal tour when she went to Dubbo, Meghan wore a grey blazer from the tennis icon's collection. 

The royal opted to wear a double-button style blazer with patch pockets and a red-and-blue windowpane pattern.