Rifling through her baby photos of the pair, the Saturdays singer realised that her two-month-old baby boy is the spitting image of her daughter back when she was a similar age.
It's true. The resemblance is uncanny!
Taking to Instagram, Una posted two photos, one of Tadhg and one of Aoife-Belle when she was much younger, alongside each other. She then told fans: "It's actually frightening how alike my two kids are! Tadhg on the left, Aoife Belle on the right."
Comparing the two little ones, it's definitely clear they are brother and sister as both are sporting the same big blue eyes, button nose and chubby cheeks.
Now that's a major 'aww' moment right there!
On seeing her post, fans were quick to comment, with many coo'ing over Una's gorgeous children.
One user said: "They are like twins!" While another commented: "Wow, they're so alike."
Earlier this year, Una welcomed her second child, Tadhg, with husband Ben Foden.
Rugby pro Ben announced his son's safe arrival on Twitter, tweeting shortly after his birth: "Tadhg John Foden has been born! Mum and baby are both amazing and healthy. He has a full head of hair and his mummy's lips! #babybenuna."
Since then the Foden family have been getting used to having an extra addition, and Una has continuously gushed about her baby boy on social media.
Recently, the Irish beauty told fans: "My heart could burst with how in love I am."
Una is currently in her native Ireland working on The Voice of Ireland alongside Rachel Stevens and Westlife star Kian Egan.
Luckily for her though, she hasn't had to go without seeing her family as Ben, Aoife-Belle and Tadhg have all joined her.
Una even brought her family with her to work over the weekend, and judging by her recent Instagram snaps, Aoife-Belle wasn't the only one enjoying testing out the spinning red chairs....
Yes, we're looking at you Ben Foden!
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