The partnership, which is a first-of-its kind for Greggs, will see 60 Primark stores across the country stock a range of 11 clothing items.
The items include hoodies featuring the Greggs logo and the message “It’s a pastry thing” written along one arm.
The news has received a mixed response on social media after Greggs shared a video promoting the collaboration on Twitter.
Some questioned whether it was a parody, while others said they couldn’t wait to get their hands on one of the pieces.
“I am ashamed about my enthusiasm for this,” one person said.
“This is absolutely barking mad…and I love it,” another said.
A third wrote: “Literally feel like this is an April fools two months early.”
Alongside the fashion line, Primark’s flagship store in Birmingham will host the world’s “largest Greggs”, opening a new café named “Tasty by Greggs”.
The 130-seater café will be open from 12 February and offer a menu of the bakery’s most popular items, such as its sausage rolls, bakes, pizza and sweet treats.
The range of clothing items will be rolled out across stores a week later, on 19 February.
Separately, a pop-up boutique housing the fashion collection will also be open on London’s Dean Street, Soho, from 17-18 February. Visits to the pop-up are by invitation only, and the booking system will be launched on Primark and Greggs social media pages on 10 February.
Raymond Reynolds, business development director at Greggs commented: “Greggs clothing is something our customers have continually asked for.
“It’s great that together with Primark we can now make our first official range available across the UK – so that fans can quite literally show their love for Greggs on their sleeves. We’ve got some great pieces that we can’t wait to share.”