President Trump posted on his Truth Social account on Friday afternoon that he just inspected the site of a new ballroom that he says will be built at the White House — as he says he is the only president ever to know how to build one.

He thanked himself for the project. “For 150 years, Presidents, and many others, have wanted a beautiful Ballroom, but it never gut built because nobody previously had any knowledge or experience in doing such things — But I do,” Mr. Trump said in a Truth Social post.

He mentioned his desire for a ballroom to be built during a February event in the East Room of the White House. Mr. Trump claimed he had offered the Biden administration to build and pay for a $100 million ballroom like the one at his Mar-a-Lago resort, which was finished in 2005. It was designed in the style of Louis XIV and modeled after the Hall of Mirrors at Versailles, according to a design publication, Veranda.

Mr. Trump told the crowd members, who were there to see him to sign an executive order banning men in women’s sports, that he would have it built. “I’m very good at building ballrooms. I’ve built beautiful ballrooms,” he told the audience to laughter, but apparently he was serious.

Mr. Trump says the ballroom will be built quickly and will be a “wonderful addition” to the White House. “These are the ‘fun’ projects I do while thinking about the World Economy, the United States, China, Russia, and lots of other Countries, places, and events,” Mr. Trump wrote.

It was unclear Friday how far planning had progressed on the ballroom project, but Mr. Trump said, “It will be built, compliments of a man known as Donald J. Trump.”