The Saturdays singer, 32, and her husband Ben Foden, 28, visited Santa's grotto yesterday evening (27 November) with their 20-month-old toddler - and took a snap to remember the occasion by.
Sharing it with her fans and friends on the social media website, Una wrote the caption: "We took Aoife to see Santa for the first time this evening thank you @UGGUK."
In the festive picture, Father Christmas is holding a cuddly reindeer which Aoife is reaching for, as daddy's carries her in his arms - bless!
Proud mummy Una is smiling at them both, and holding on to rugby player Ben's crutches after his recent operation to repair ankle ligaments.
Fittingly for the UGG Christmas Grotto at Duke of York Square in London, both Una and Aoife were also gifted matching UGGs.
Other celebs attending the event included Leah Wood, Jo Whiley, Tina Hobley and Emma Willis.
Earlier this week, Una and Ben showed their sense of humour when they re-created Kim Kardashian and Kanye West's raunchy 'Bound 2' music video.
The loved-up husband and wife are spending lots of quality time together as Ben recovers from his recent surgery.
Are you getting into the Christmas spirit yet, like Una and Ben? Tell us below!
Watch The Saturdays' video for single 'Disco Love':