The pregnant Duchess of Cambridge attended Westminster Abbey in London with Her Majesty the Queen.
Joined by several senior members of the royal family, Kate wore a Beulah London Chiara coat which covered her baby bump.
Kate also wore a Lock and Company hat, Rupert Sanderson heels and a new Jimmy Choo clutch in navy.
Prince William and Kate will soon have a new member of their family who will be fifth in line to the throne.
News of the third royal baby broke in September last year, and the pregnant Duchess has been keeping up with her work commitments ever since.
Bookmaker Coral is offering odds of 8-1 on Kate’s third baby being born on the same day as the couple’s seventh wedding anniversary, April 29.
Viewers instantly took to social media following Kate’s TV appearance this afternoon.
One onlooker tweeted: “Kate’s bump! #CommonwealthDay.”
“Watching the Fab Four (Prince William and Kate, Prince Harry and Meghan) attending the #CommonwealthDay service with Her Majesty The Queen,” posted another.
A third added: “@RoyalFamily @wabbey Look at Kate’s baby belly!! She is gorgeous!!”
“@RoyalFamily @wabbey The bump is huuuuge,” wrote another.
A fifth said: “@RoyalFamily I don’t think she’s ever worn a dress that showed the bump that much.”
Today’s service featured readings and live music, including a performance from former One Direction member Liam Payne.
Liam performed live at the event and spoke about the importance of having a united nation ahead of the event.
Revealing his choice of song, Liam explained: “So today I will be performing John Mayer, Waiting on the World to Change.
“I think it’s quite apparent for the way that the world is at the moment and I’m also a big fan of John Mayer. I think this is the perfect occasion for it.”
The former X Factor star went on to add: “I went down to the presentation and it was so nice to see so many young people doing so many amazing things, you know, across nations.
“It’s so important for us to show a nice united front right now and coming from the youth is a really beautiful thing I guess.”
A Service of Celebration for Commonwealth Day is available to watch on BBC One now.
