The pair will serve hand-rolled pasta, nose-to-tail cooking, game and charcuterie.
Cardiff chefs Tommy Heaney and Dave Killick will open their new neighbourhood restaurant and bar, Ember, in Pontcanna on 6 December.
Heaney, founder of Heaneys and Uisce, is partnering with Killick, former head chef at Heathcock, to showcase Welsh produce at the 50-cover diner.
The menu will focus on hand-rolled pasta, nose-to-tail cooking, game and charcuterie.
Heaney said: “Dave and I have been friends for years and have always supported each other’s ventures. I’d love to tell you this was a well thought-out dream of ours, but in reality, we were having a drink in the pub, one thing led to another, and here we are. The opportunity came up and we couldn’t say no, it’s literally across the road from my restaurants.
“I’m really excited to see what we can produce between us, Dave loves making pasta and I love his style of food. This is anything but Italian – we are using the best of British.”
Heaney, who was formerly head chef at Bar 44 in Cowbridge and the Low Wood hotel in Windermere, Cumbria, opened his first solo restaurant, Heaneys, in October 2018.
Heathcock is a Michelin Guide-listed neighbourhood pub that operates as a sister site to the Hare & Hounds in Aberthin.
The restaurant had originally been due to open in September.