Welsh referee Nigel Owens will take charge of Wales' game against the Barbarians on November 30.
Announcing his appointment, the Welsh Rugby Union said Owens had received "special dispensation" from World Rugby for the fixture.
It is thought to be the first time such an appointment has been made when a referee officiates a game featuring his own country.
Owens, 46, refereed the 2015 World Cup final between New Zealand and Australia, and is among officials chosen for the 2019 global showpiece, which kicks off in Japan later this month.
The Principality Stadium clash will be Wales' first match under Wayne Pivac, who succeeds Warren Gatland as head coach after the World Cup, with Gatland coaching the Barbarians.
Tickets go on sale at 10am on Thursday 5th September via the WRU's official ticket office website.