And although the royal is out on duty today during his wife, Kate Middleton's 37th birthday, it is expected that they will spend the evening together alongside their children.
Kate, 36, wore a blue Catherine Walker coat which she was first seen in when pregnant with Prince Louis last February.
Back in 2017, the royal opened up about the impact gardening had on her family while visiting London's Robin Hood Primary School: "I've got such fond memories of being in the garden and being outside from my own childhood, and I'm sharing that with my own children, George and Charlotte, at the moment".
And it's no doubt that this campaign or line of work is close to William's heart, as he operated as an East Anglian Air Ambulance pilot from 2015 to 201.
A birthday isn't complete without an onslaught of social media wishes - even from the royal family!
IAN VOGLER via Getty Images The Duke of Cambridge walks across the helipad after arriving in a red London Air Ambulance at the Royal London Hospital in east London on January 9. William - a former search and rescue helicopter pilot in the Royal Air Force - will work as a co-pilot transporting patients to the hospital in emergency situations.
It's also likely the extended Cambridge family will join in on the celebrations.
The Duke and Duchess of Sussex first appearance of the year will be on January 14.