All drew attention to the neckline of the dress Middleton - she usually prefers a more restrained manner, but this time decided to make a bold accent. "Less is more for this new mum-to-be". Sign up for our newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!
Naturally, she looked flawless at both formal events.
This week, the royals released a brand-new photo of Louis, with the shot finding the prince being introduced to his grandfather, Prince Charles, by Middleton.
As you know if you have an internet connection and a fledgling interest in the royals, Kate Middleton and Prince William are very much in the spotlight.
Little sister Princess Charlotte followed suit on May 2, 2015. She pulled out the ensemble again at the Queen's official birthday celebrations, Trooping the Colour, in 2016.
Next week Prince William and Kate William will also be busy with official business. "The boots only get better with age".
Tusk works to protect African wildlife and fights the illegal trade of animals including elephants, and Prince William earlier this year visited Tusk projects in Namibia and Tanzania.
The Duke and Duchess of Cambridge stepped out for an appearance at the Tusk Conservation Awards in London on Thursday night.