Coleen, 28, posted the sweet snap on Facebook earlier today (20 May), and it shows Klay sat on the kitchen floor alongside a single blue helium balloon.
Klay appears to be dressed in his pyjamas and looked cute as a button as he posed for his mummy.
Alongside the photograph, Coleen commented: "Happy 1st Birthday to my Klay xxx."
Last night, Coleen also tweeted a snap to her fans, which showed a dining room table laden with presents, balloons and a beautifully decorated cake.
"Can't believe my baby is 1 tomorrow!!! Time goes TOO quick!!" she commented.
Coleen and her footballer husband Wayne, who are also parents to four-year-old son Kai, are currently in Portugal with their kids for World Cup training.
Hope you're having a great day, guys!
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