The London burger brand first acquired a 1,500 sq ft site in the seaside city’s busy South Lanes area last year.
The 50-cover restaurant will be the group's first launch outside the capital, offering the same menu as the its London sites including the Ari Gold cheeseburger and Hot Chic chicken burger.
Patty & Bun currently operates nine sites in London and has a permanent residency at golf venue Swingers LDN.
Property agency Shelley Sandzer acted for Patty & Bun to secure the Brighton site.
“We are really excited to kick off 2018 with the opening of our first restaurant outside of London,” says Joe Grossman, founder of Patty & Bun.
“[We] are looking forward to working with Shelley Sandzer again as part of our regional growth in the UK.”
Patty & Bun started out as a London pop-up before launching its first permanent restaurant in 2012.