The Duchess of Sussex, 38, shared a sweet message in a special post on the couple’s Instagram account - which also featured an unseen photo from their four-month-old son Archie’s christening.
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She wrote: “Your service to the causes you care so deeply for inspires me every day.
“You are the best husband and most amazing dad to our son. We love you. Happiest birthday!”
The message, shared on the @SussexRoyal account this morning, accompanied nine photos from important moment’s in the Duke of Sussex’s life which were arranged in a collage.
They show Harry in separate situations with mum Princess Diana, brother Prince William and the grandfather Prince Philip - although his dad Prince Charles, Kate Middleton and the Queen are not included.
There are also pictures of him embracing Meghan at their 2018 royal wedding, as well as serving in the army and carrying out official royal duties.
However, it is the first time a black and white image - included in the bottom-right of post - has been published.
The candid photo, taken by their go-to photographer Chris Allerton, shows Harry kneeling down in front of Meghan who is holding Archie at their firstborn’s christening in July.
It is understood that the Duchess plays a crucial role in the running of the Instagram account - making the choice of images and caption particularly special.
Further evidence of her direct involvement in today’s post comes from the American spelling of the word “color” in a photo credit at the end of the post.
In fewer than two hours, it had already received more than 200,000 ‘likes’ and more than 3,000 comments.
However, Meghan hasn’t been the only royal to send Harry birthday wishes today.
The Duke and Duchess of Cambrideg’s Instagram account, @kensingtonroyal, posted a picture of the brothers together, along with the caption: “Wishing a very happy birthday to The Duke of Sussex today!”
Additionally, the Prince of Wales and wife Camilla, Duchess of Cornwall’s Instagram account - @clarencehouse - also shared images of father and son, writing: “Wishing a very Happy Birthday to The Duke of Sussex, who turns 35 today!”