Porro will be a 60-cover venue serving modern British and ‘Italian-ish’ food.
Dishes will include Cod Cheeks and Cockles on Toast; and Tagliatelle with White Broccoli, Buffalo Mozzarella, Roast Garlic and Breadcrumbs.
Cerys Furlong, who opened The Potted Pig with husband Tom Furlong and co-chef Gwyn Myring in 2011, described the new restaurant's development as a 'whirlwind'.
“We really want Porro to be part of the Llandaff community," she said.
"We will be open 7 days a week and look forward to welcoming a range of diners - from those looking for a working lunch, to parents on the school run."
Despite opening under the same team as The Potted Pig, Porro has been designed to have a distinct identity.
“The menu will use seasonal, local produce, with some ingredients exclusively sourced from Italy," said Furlong.
"The drinks menu will carry a range of independently sourced wines, as well as bottled lagers, ales and ciders to be reviewed on a regular basis.”
Porro will open at 22 Highstreet, Llandaff, Cardiff.