Posting examples of cards to social media, Kensington Palace wrote: “Each year on Mother’s Day, George, Charlotte and Louis make cards remembering their Granny, Diana, for William.
“Whatever your circumstances, we are thinking of you this Mother’s Day.”
They added that this year’s Mother’s Day will be different “once again” as many spend it apart from their loved ones.
And that for those experiencing bereavement “today may be particularly challenging”.
Many shared their thoughts on the post, saying it was a “lovely tribute”.
“What a lovely tribute. Thank you for sharing this,” one person commented.
Another said: “This is so beautiful and moving. What a lovely thing to do.”
Prince William was 15-years-old and Prince Harry was 12 when Princess Diana died in a tragic car accident in 1997.
To honour their mother, it has been reported that the two brothers will come together to attend a memorial unveiling a statue for Diana this summer.