Primark will open its first store in Chester by occupying the former Woolworths shop owned by Redevco.
Redevco appointed architects Leslie Jones to design a double height shop front at the building in Foregate Street in January.
The existing building was designed by the Building Design Partnership.
Leslie Jones stated the first floor brick work would be removed and replaced by full height glazing to deal with the "poor quality" appearance of the front of the building.
Fashion retailer Primark was understood to be occupying the building at the time.
Since then Primark has signed up to the building on the condition that planning would be granted for a 7,000 sq ft extension, which has now been given the green light by Chester City Council.
Work on the four-storey property will include a first floor extension to the rear of the building and the replacement of ground floor brickwork with a fully glazed shop frontage.
HOW Planning, based in Manchester, are acting as planning advisors.