The firm used social media and local outlets to drum up interest from customers in taking a ride in a karaoke cab that spent a day in Liverpool and a day in Manchester last week.
Content captured of its passengers will be published in the coming weeks across Instagram, Facebook, Youtube, Twitter, Snapchat and a specially designed microsite.
The cab was complete with a unicorn horn, and reflected the 'New Fashioned Christmas' concept created by Uniform, which is working on its inaugural project for Primark.
It's a wrap! Check out all the fun from our #Unicorncab karaoke event here: https://t.co/M3ssFwdbeX pic.twitter.com/dDZ2PTIu0Z
— Primark (@Primark) November 30, 2017
The New Fashioned Christmas theme is also replicated in store, with various images of models captured at a separate photoshoot.
There is no TV advertising accompanying the Primark campaign, a Uniform spokeswoman confirmed.
The first FAQ on the company's website explains that its low-advertising model is one factor in keeping its prices low, saying: "We also choose not to spend money on things that other retailers might. You might have noticed for example that we don’t do TV advertising or hardly any other advertising either."