"The Duke and Duchess of Sussex will both speak at the ceremony this evening", the tweet read, giving photo credit to Markle herself.
Markle is following in the footsteps of her sister-in-law Kate Middleton, who also takes frequent photos published to social media of her children Prince George, Princess Charlotte and Prince Louis. He said Harry had no idea, and clearly didn't know much about basketball.
The embellishment on the dress was made by French design Sarah Esmoingt, who works for Oscar de la Renta and Zac Posen, fan site Meghan's Mirror revealed.
Milda said: "The Duchess of Sussex has had an excellent travelling wardrobe so far, with a far more relaxed manner towards her clothing options compared to the Duchess of Cambridge during her tour. How long did it take?"
"I want to be a fashion designer when I grow up - this is a good start".
The royal couple's tour to will continue following a stop in Australia.
Next on the busy afternoon was laying a wreath at the National War Memorial.
Meghan chose the Invictus closing ceremony to make her only public speech of the Australian leg of the tour, praising the hundreds of friends and family who supported the competitors all the way to the finish line and beyond.
The memorial, which features stained glass leaves and has the silhouette of a soldier between the branches, was unveiled by then-foreign secretary Boris Johnson in July 2017. They also met with political leaders.
The founder of company Outland Denim, Jamie Bartle, revealed he had to hire 15 more staff members after sales jumped by 950% when she wore a pair of the brand's pants.
Their royal highnesses were invited to hongi with the Governor-General's Kuia and Kaumatua (Maori elders) as well as to a haka performed by members of the New Zealand Defence Force.
Britain's Prince Harry accepts a traditional challenge by Maori warriors during an official welcoming ceremony at Government House in Wellington.
On Monday, the couple will travel to Abel Tasman National Park for a series of engagements about conservation.