The Principality Stadium, the national stadium of Wales, is to be used as a field hospital for up to 2,000 beds to help fight the coronavirus.
The Cardiff and Vale University Health Board and Welsh Rugby Union have come together to make the stadium available.
The stadium has served as a temporary hospital for ambulance services before.
"I understand the concern that this will cause, not only in the community but among my staff too," said the health board's CEO Len Richards.
"However we are planning on the basis of what we think we might need to ensure we are as ready as we can be.
"I sincerely hope we don't need to use all of the capacity but it is far better to have developed plans based upon the scientific evidence and modelling of the experts."
Richards stated that the temporary field hospital at the national rugby stadium of Wales, would have the "capacity to hold up to an additional 2000 beds."
Wales' Health Minister Vaughan Gething confirmed he had approved £8m of funding for the project.
The WRU chief executive Martyn Phillips said: "It is a privilege to be able to offer our services, facilities and a significant number of operational staff, at their individual choice, to help at this time of national emergency.
"We have made advanced plans to transform relevant spaces into fully functional hospital environments."
Welsh Pro14 region Scarlets have also made their Parc y Scarlets rugby stadium in Llanelli available. while Rodney Parade in Newport and the Liberty Stadium have also been offered to the emergency services.
Leisure centres and other public buildings in Carmarthenshire are also to be turned into hospital wards to help health services cope with demand.