The Duchess of Cambridge, 40, celebrated her milestone birthday on Sunday and received waves of well wishes. However, one that stood out to the Duchess was from little Mila Sneddon who had met Kate previously.

       The pair share a special relationship after Kate first met Mila, who is battling a rare blood cancer, in May last year.

       The six-year-old was recently discharged from hospital after testing positive for Covid and she remains in isolation at home.

       Young Mila will resume chemotherapy once she has fully recovered from the virus.

       Wishing the Duchess a happy birthday, her mother posted a video of Mila on Twitter where she said: “Happy Birthday Catherine.

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       “I'm so happy you're turning 40, hope you get nice gifts and love spending time with your family. Bye, lots of love, Mila.”

       The Tweet amassed nearly 6,000 likes and hundreds of comments, but one comment caused a royal fan frenzy.

       The Duke and Duchess of Cambridge’s official Twitter account sweetly replied: “Thank you Mila!”

       Many royal fans took to Twitter to gush over the cute encounter.

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       Judith commented: “I love the special bond the Duchess has formed with this extraordinary girl.”

       A royal fan account @loveforcambridg wrote: “Aw how nice of you to reply to her. I’m sure it will make her smile.”

       Ella wrote: “This is so lovely. You just made Mila’s day, for sure.”

       Another Twitter user wrote: “This sweetness will make me cry.”

       Another commented: “This just melted my heart - bless you Mila…this was really sweet & the icing on the cake - Catherine responded…”