Donald Trump has been envisioning a new ballroom on the White House campus for a decade and a half.

His dream is about to become a reality.

Construction will begin in September on a $US200 million ($310 million), 8400-square-metre ballroom, his press secretary announced overnight, fulfilling a 15-year ambition by the president to construct an event space on the White House grounds that expands the building’s entertaining capacity — but also resembles the gilded spaces of his private clubs.

Renderings provided by the White House depict a vast space with gold and crystal chandeliers, gilded Corinthian columns, a coffered ceiling with gold inlays, gold floor lamps and a checkered marble floor.

Three walls of arched windows look out over the White House’s south grounds — including a massive new flagpole that was another of Trump’s additions to the historic compound.

“I always said I was going to do something about the ballroom, because they should have one,” Trump told reporters.

“It’ll be a great legacy project, and I think it’ll be special.”

Press secretary Karoline Leavitt said the new “state ballroom” would occupy space currently housing the East Wing of the executive mansion, where first ladies have traditionally maintained offices.

Staff working from the location now will be “temporarily relocated”.

The renderings show the exterior of the ballroom jutting onto the South Lawn, with a colonnade running along one wall.

A Palladian facade with columns and a pediment sits on the eastern wall.

The gold-and-white style closely mimics the Louis XIV-style main event room at Mar-a-Lago, Trump’s estate in Palm Beach.

Trump has not shied away from drawing inspiration from his clubs.

“No president knew how to build a ballroom,” Trump said last weekend, meeting the European Commission president in another of his crystal-draped ballrooms, this one at his Turnberry golf resort in Scotland.

“I could take this one, drop it right down there, and it would be beautiful.”

The new ballroom — which will maintain the “theme and architectural heritage” of the neoclassical executive mansion, the White House says — will have a seated capacity of 650 people, more than three times the space in the East Room, currently the largest event space in the White House.

“President Trump is a builder at heart and has an extraordinary eye for detail,” White House chief of staff Susie Wiles said in a statement.

“The president and the Trump White House are fully committed to working with the appropriate organisations to preserving the special history of the White House while building a beautiful ballroom that can be enjoyed by future Administrations and generations of Americans to come.”

Leavitt characterised the new construction — which she said will be funded by Trump and other private donors — as a necessary addition after previous White Houses were forced to host major events in a temporary tent constructed on the South Lawn, which she called “unsightly”.

“For 150 years, presidents, administrations and White House staff have longed for a large event space on the White House complex that can hold substantially more guests than currently allowed,” she said.

“President Trump has expressed his commitment to solving this problem on behalf of future administrations and the American people.”

Trump, she said, had convened meetings recently with officials from the National Park Service, the White House Military Office and the US Secret Service to “discuss design features and planning.”

An architect known for “classical architectural design,” McCrery Architects, was selected to spearhead the project.

“I am honoured that President Trump has entrusted me to help bring this beautiful and necessary renovation to The People’s House, while preserving the elegance of its classical design and historical importance,” the firm’s CEO Jim McCrery said in a statement.

The vision of a new White House ballroom floated in Trump’s mind dating back at least to 2010, when he called Barack Obama’s White House offering to build one.

“It was going to cost about $100 million,” Trump said during his first term.

“I offered to do it, and I never heard back.”