The Saturdays star, 32, took to Instagram to announce her pregnancy. She shared a sweet snap of the couple's daughter Aoife Belle holding her hands above her head and wearing a T-shirt which read, "I'm going to be a big sister."
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Una Foden shared her happy pregnancy news with this photo of daughter Aoife
Writing alongside, Una told fans, "I know lots of people have been guessing and Ben and I can no confirm that Aoife is going to have a baby brother or sister next year!!! We're all very happy."
Una and rugby player Ben, 29, welcomed their first child in March 2012, and were married in the singer's native Ireland in June that same year.
Una Foden and her husband Ben Foden
The new arrival will be the fourth Saturdays baby – Rochelle Humes and her husband Marvin welcomed their daughter in May 2013, while Strictly star Frankie Bridge became a mummy to son Parker in October.
Earlier this year, Una spoke about her dreams of expanding her family. "I would love to have more kids further down the line," she told the Metro. "I very much enjoy being a mum."