The actress said next year was going to be “difficult” without her relative and “matriarch” of the family.
The 38-year-old took to Instagram to break the news to her 807,000 followers today, while sharing a snap of her doppelgänger grandma.
Sporting the same dark tresses, she was pictured in a pale jumper and it wasn’t long before fans remarked on their likeness.
Kelly wrote: “Missing you so much Grandma Kelly. 2018 is going to be difficult without you!”
The brunette beauty continued: “I love you with all my heart. You were our Matriarch. Funny, clever and so talented. An artisan and a stunningly beautiful lady.
“Daughter, Sister, Wife, Mother, Grandmother and Great Grandmother. Sleep beautiful my Angel.”
Kelly was inundated with sympathetic replies, with one fellow user writing back: “Sorry for your loss Kelly @iamkb.”
Two others continued: “Kelly you are so like her,” and: “It seems your beauty is inherited from her.”
“Sorry to hear of your loss, you really look like her… So it’s a legacy to her, that you inherited her beautiful looks,” a fourth went on.
Meanwhile, Kelly has been keeping her fans updated on her festive celebrations, after stepping out at The Ten Year Tale party in aid of cancer charity Teens Unite earlier this month.