TV actor Neil Morrissey says he is "very excited" to have bought the pub, which is believed to have inspired famous Welsh writer Dylan Thomas.
The star of Men Behaving Badly bought Brown's Hotel in Laugharne, west Wales, for £670,000 at auction.
The Grade II listed building was put on the market last May by landlord Tommy Watts, but failed to sell.
The pub, which was sold as a going concern, had been expected to sell for £400,000.
Mr Morrissey, who was not at the sale because he had been recording the children's TV series Bob The Builder, was represented by his business partner Matt Roberts.
They already own the Hurst Hotel in the village and the New Three Mariners pub nearby.
Mr Morrissey said on Thursday: "I'm very excited to be expanding the business in what I consider to be my second home."
Mr Roberts spoke to the actor immediately after Wednesday evening's sale.
He said: "He just whooped very loudly, and has now gone dancing in a club in London."
Bidding quickly started at £350,000 before reaching the selling price, which Mr Roberts called "spot on."
The Dylan Thomas connection played a "massive" part, he admitted.
He said: "That's why we moved down here in the first place, it's a very proud moment."
The pub has changed little since Thomas used to drink there
Mr Roberts said they intended to retain the character of the 250-year-old building and described Laugharne as potentially "the biggest tourist attraction in Wales."
More than 300 people packed the Memorial Hall in the village for the sale.
Former owner Mr Watts, 73, told how Thomas regularly watched the pub's clientele to get ideas for his characters in his radio play Under Milk Wood.
"He was always in the corner," he said.
"He would take out a little pad and would write a comment."
Mr Watts, who has owned the pub for more than 30 years, added that the pub had not changed at all since Thomas, who died in 1953, was a regular.
Famous visitors to the inn since have included Richard Burton, Elizabeth Taylor, Mick Jagger and Pierce Brosnan.
Dylan Thomas was inspired by people in Laugharne
But Mr Watts said that there was no special treatment for celebrities.
"Everyone is just treated as normal, they love coming here," he said.
Although born in Swansea, Thomas and his wife Caitlin moved to Carmarthenshire in 1938, raising their family in the Boat House overlooking the estuary.
Estate agent Terry Thomas said Brown's was "an integral part of life for many people in Laugharne".
Mr Watts said he was happy with the price and will stay in the village but he and his wife plan to use some of the money to visit their son and grandchildren in Australia.
His wife Meresa said they planned to throw a party for pub regulars the weekend before they left and all the drink would be on the house.
"They can drink the bar dry," she added.