Charles and Camilla live near the rugby club, when in Wales
Prince Charles has become patron of the rugby club near the retreat which is his base during summer tours of Wales.
The Welsh Rugby Union said Llandovery rugby club in Carmarthenshire is the first in Wales to have royal patronage.
Club chairman Handel Davies said the news had "created a real buzz about the place and lifted everyone for the season ahead".
The Prince of Wales renovated the farmhouse, Llwynywermod, a few miles from the club, near Myddfai.
The 192-acre (78 hectare) former coach house and estate was bought by the Duchy of Cornwall in 2006.
The Welsh Rugby Union said Mr Davies and members of the Llandovery club broached the idea of link with the prince when they were invited to visit the house with other local personalities and dignitaries after Charles and Camilla, Duchess of Cornwall, took up residence at the property in June 2008.
But it was only when the prince returned to the club late last month that Mr Davies learned his request had met with approval.
Mr Davies said: "It was a great honour to be invited to the prince's residence in Wales in the first place and he was so welcoming and accommodating when I met him that it just seemed natural to me to come right out and ask him.
"He said we should write to him, but we certainly didn't expect him to respond in this way during a personal visit and we have been overwhelmed by the good news.
"Prince Charles spent hours talking to each and every member of the club on his visit, walking up and down lines and lines of our different age group teams.
"He unveiled a plaque to officially open our new terrace and to hear he was willing to become an official patron was just the icing on the cake for us.
"The club is the real heart of the community here and to be able to claim association with the prince, and to be the only club in Wales who can do so, is a boost to everyone in Llandovery."
The Queen is the official patron of the Welsh Rugby Union and Prince William became the vice royal patron of the WRU in February 2007.
The Prince of Wales himself is a patron of the London Welsh club, but this is his first association with a club in Wales.