Other royal fans were quick to take to social media to congratulate the couple who share children, Prince George, Princess Charlotte and Prince Louis.
"Happy wedding anniversary. Diana would be so proud of you both," wrote one fan.
Another added: "Wishing your Highnesses a very happy wedding anniversary."
A third chimed in: "Happy Anniversary to the most beautiful couple. Both so gorgeous."
Wills, Kate and their children are currently self-isolating at Anmer Hall in Norfolk, as the UK battles the coronavirus pandemic.
The Duke and Duchess have continued with their royal duties despite being in lockdown.
Their most recent appearance includes the entire Cambridge clan appearing on the steps of their home to join in the nationwide 'clap for our carers' on Thursday night to raise funds for NHS Charities.