The gorgeous Irish singer and the rest of the Saturdays hit the stage in Dublin on Wednesday evening (17 September), where Una looked gorgeous in her sparkly costume.
Una's baby bump was visible as she performed at the Olympia Theatre on the latest date of The Saturdays' current 'Greatest Hits Tour Live'.
She later tweeted: "Dublin you were THE best!!! #greatesthitslivedublin."
The 32-year-old announced earlier this month that she and rugby player husband Ben Foden are expecting their second child together next year. They're already parents to daughter Aoife Belle, two.
It will be the fourth Saturdays baby as Rochelle Humes is mum to daughter Alaia-Mai, one, and Frankie Bridge has son Parker, who turns one in October.
One more and they'll have enough for a mini Saturdays!
Una was pictured earlier in the day looking make-up free and absolutely stunning as the band touched down at Dublin airport ahead of the show.
And later on, she was pictured meeting with fans outside the Olympia Theatre, taking pictures and signing autographs.
Life is good for Una right now!