The loved-up couple, who moved house last week, joined Billi's BBF and former TOWIE co-star Cara Kilbey at the Christmas hotspot in Hyde Park for rides and mulled wine.
Billie couldn't wait to share some pictures of their evening out together with fans and, to be fair, it couldn't have looked more Christmassy!
In one snap, Billi is cosying up next footballer Andy - who popped the question last month - outside the main entrance to the theme park.
Along with a selection of festive emoticons, she simply commented: "Christmas Countdown!"
The yoga instructor also posted a close-up selfie on Instagram, adding: "Winter Wonderland with my [heart] #christmas #excited @andytcarroll."
Having only begun dating earlier this year, this is Billi and Andy's first Christmas together. No wonder they're excited!
Meanwhile, Billi also caught a picture of Andy as he toasted marshmallows on an open fire, while Cara posted a snap of herself and a male friend on Instagram.
Last month, Andy whisked Billi off to Italy for her 26th birthday and proposed during a romantic meal together.
They have since moved in to a new house together and it is thought they are planning a wedding for next year.
Have a great Christmas, guys!
Couples who have got engaged in 2014:
Copyright: Instagram kayascods