The Royal Commonwealth Society is making plans to open a branch in the United States, with a view to one day bringing America into the fold as an "associate member".
The project, which is said to be backed by the Queen, has come about in part as a result of Donald Trump's fondness for Britain and the royal family.
It comes amid efforts to develop the Commonwealth as a tool for building relationships on everything from foreign policy to trade, following Britain's exit from the European Union.
"The UK rather left this treasure in the attic, and forgot about it because people were so glued to Brussels," said Michael Lake, the director of the Royal Commonwealth Society.
Opening a branch in the US, Lake said, would further Britain's ties with America, developing new connections between two countries who already share a common language.
Lake said the plans had been hastened by the "opportunity of a new president, and the slightly dangerous but great fun opportunity that the 'Bad Boys of Brexit' offered".
In December, Lake wrote a letter to Trump, which was hand carried by Andrew Wigmore, a close aide to Nigel Farage, and then delivered by the former UKIP leader.
Wigmore joined Farage and Arron Banks, the millionaire businessman in visiting Trump after the US election, and continues to have close ties with the administration.
Farage, who has emerged as a key ally of Trump, promoted the idea with senior aides, reportedly presenting the letter to Steve Bannon, the president's chief strategist.
He believes the Commonwealth alliance fits well with Mr Trump's foreign policy outlook.
The president, for example, is said to have expressed his desire for India to be a "true friend and partner" in a phone call with Narendra Modi, the country's prime minister.
Lake wrote in his letter that opening a Commonwealth branch in America would help the UK and the US "find imaginative ways" in which they could work together.
Wigmore told the Telegraph the response from the White House was "very positive".
Though Lake has not yet received a formal confirmation, discussions are said to be already underway to establish the office in New York.
It is part of an effort by Lake to raise the profile and relevance of the modern Commonwealth, seeking to make it more of a factor in matters of foreign policy.
"It has been very introspective, it needs to more extrovert," he said. "In that sense we have adopted a policy of getting branches of the Commonwealth in non-commonwealth countries."
The idea, he said, is to promote "mutually advantageous" links with "reliable friends" around the world on everything from business to defence.
The advantage of the Commonwealth, Lake said, is that it operates less formally than governments, as a loose arrangement that is furthered by common values and culture.
"It works because companies find it easier and more congenial to work in Commonwealth countries," he said.
A new branch of the RCS has already opened in Helsinki, acting as a Baltic-Scandinavian hub, to help facilitate business ties with Commonwealth countries.
Last year the RCS opened a chapter in Dublin, as part of a campaign to help persuade the Republic to rejoin the alliance of 52 member states.
Lake said it was "no secret" that the branch there was opened after the Queen undertook a state visit to the country.
"The Queen is our patron and I see her from time to time, and she makes it clear to me that the Commonwealth is a priority to her," Mr Lake said.
Trump, whose mother is Scottish and a royalist, has also expressed his enthusiasm for building his connections with the Royal family.
He is hoping to visit Her Majesty at Balmoral Castle during his first official state visit to the UK in June.