William and Kate share sweet personal photo of the Queen to celebrate her birthday

Today marks the Queen's 96th birthday, with the monarch said to be spending the day at Sandringham as a touching tribute to her late husband, Prince Philip. She will later be joined by members of the royal family, some of whom have already taken to social media to share sweet messages for her on this special day.

One particularly sweet message came from her grandson, Prince William, and his wife, Kate Middleton, who decided to share a sweet personal photo as well as their well wishes.

Calling her an 'inspiration', the Duke and Duchess of Cambridge posted an adorable picture of the Queen and Prince Philip sat on the sofa alongside seven of their great grandchildren. The photo was taken by Kate, who is often behind the lens when it comes to the official portraits of her children, and shows the monarch looking happy and relaxed with the little royals.

She can be seen smiling with the Cambridge children, Prince George, Princess Charlotte and Prince Louis, as well as Peter Philip's daughters Savannah and Isla. Zara and Mike Tindall's children, Lena and Mia, are also present.

Sharing their congratulations, the Cambridges wrote: 'Wishing Her Majesty The Queen a very happy 96th birthday today! An inspiration to so many across the UK, the Commonwealth and the world, it’s particularly special to be celebrating in this #PlatinumJubilee year.'

The Queen also shared new portraits to celebrate her birthday, with images of the monarch standing between two white horses and wearing a green coat - said to be a sweet nod to Prince Philip.

Taken in the grounds of Windsor Castle back in March, the photo by Henry Dallal shows the Queen with her two ponies, Bybeck Nightingale and Bybeck Katie.

Happy birthday to Her Majesty!