The Celtic Collection has been appointed to operate the Welsh Rugby Union's Westgate hotel in Cardiff when it opens.
The 175-bedroom hotel is a joint venture between the WRU and property developer Rightacres.
The project is awaiting planning permission from Cardiff Council to transform the Grade II-listed former Post Office building on Westgate Street, one of the oldest buildings in the Welsh capital, and the former Inland Revenue building, later known as the County Court, into a four-star hotel.
The group had originally hoped to start construction in June with a launch date slated for December 2020.
The hotel, near the Principality Stadium, would also feature "one of the largest function rooms" in the city, capable of seating 350 guests, a bar, a 120-cover restaurant, and a spa with a swimming pool and "views over the city"
The project is being funded by Legal & General as part of its ongoing investment into the regeneration of Central Square.
The Celtic Collection also includes the five-AA-star, 330-bedroom Celtic Manor Resort in Newport; adjoining four-star Manor House with 70 bedrooms; the nearby 148-bedroom, four-AA-star Coldra Court hotel; the recently rebranded Tŷ hotel in Magor, the first property under the new brand following the acquisition of the former Hampton by Hilton Newport East; and the Newbridge on Usk Inn.