Royal fans have praised the sweet family images - taken by Kate Middleton - of the Duke of Cambridge playing with their kids in the garden of their country home Anmer Hall in Norfolk.
One shot shows the hands-on royal father - who also turns 38 today - posing on a swing with Prince George, six, Princess Charlotte, five, and Prince Louis, two.
Since being posted on Instagram, it has received more than 1.9m ‘likes’ with more than 21,000 people also leaving delighted comments.
One person wrote: “Amazing family.”
Another commented: “Prince William looks so happy! Fatherhood suits him.“
A third shared: “All the kids look so grown up!”
And a fourth added: “This is ADORABLE.”
Many social media users also revealed their admiration for Charlotte’s denim playsuit, which she wore with a striped T-Shirt.
There were also several who drew attention to the likeness between her brothers, who they suggested looked “like twins”.
The caption explained that the candid photo had been taken earlier this month.
A second image, featuring the duke being sweetly wrestled by his children on the grass, has been shared to mark today’s double celebrations for the family.
Since the middle of March, the family have remained at their Norfolk home - which is near the Queen’s Sandringham home.
Having conducted a string of virtual engagements via video call, this week the duke and duchess returned to in-person engagements.
William joked about being ready to get back to the pub during a visit to a bakery in King’s Lynn.
Speaking about what he had been getting up to in lockdown, the second-in-line to the throne said: “I’ve done a little bit of baking.
“The children have been attacking the kitchen and it’s just been an explosion of flour and chocolate everywhere.
“Catherine’s been doing quite a bit of baking.”
His 94-year-old grandmother has been in isolation in Windsor Castle since the beginning of the pandemic.
Meanwhile, the duke’s father, Prince Charles - who experienced mild coronavirus symptoms in March - also returned to face-to-face engagements with wife Camilla, the Duchess of Cornwall.