Phil Bryant, the Governor of Mississippi, praised Mr Farage as a “humble man who just believes in Great Britain” at a lavish party thrown for the former Ukip leader at the five star Hay Adams hotel, overlooking the White House, on Thursday night.
He said: “There is an opportunity for him to work directly with the President, we call it ‘close but unofficial’.
“I think you will see that type of relationship between Nigel Farage and the President where he will turn to Nigel for advice about Great Britain.”
Mr Bryant added: "I don’t want to speak for the President but I know that the president has a great deal of trust in Nigel Farage, and I think he is going to turn to him as an adviser and there would be none better."
The news is likely to stoke anxieties in Downing Street, which has desperately tried to downplay Mr Farage’s significance after Mr Trump said he would make a good ambassador to the US in November.
The former Ukip leader is tipped to play an informal advisory role for the president.
The President and Mr Farage were introduced by Mr Bryant on the closing night of the Republican National Convention in Cleveland, Ohio, in July.
The pair became close allies after Mr Farage gave a speech at the convention, and the 52-year-old campaigned for the billionaire Republican in the final months of the presidential race.
The party, organised by US public affairs firm Goddard Gunster, was attended by around 200 guests including millionaire Ukip donor Arron Banks, Tory MP Nigel Evans, and Lord Ashcroft.
Mr Trump was sworn in today as the 45th president of the United States.
Mr Farage at the party described Mr Trump’s victory at the party as part of a “global revolution”.
He said: “Brexit was great but Trump becoming the president of the USA is Brexit plus, plus, plus.”
“I have spent most of my life in politics as the patron saint of lost causes, having to spend several hours every day drowning my sorrows with English pints of beer because that’s all I ever did.
Donald Trump becomes 45th U.S. PRESIDENT
Fri, January 20, 2017
The inauguration of Donald Trump as the 45th President of the United States will mark the commencement of the four-year term of Donald Trump as President and Mike Pence as Vice President. A public ceremony will be held on Friday, January 20, 2017, on the West Front of the United States Capitol Building in Washington, D.C.
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US President Donald Trump points to the stands as he walks with his wife Melania during the Inaugural Parade.
“I really believe this for most of my life what happens in America in terms of social trends or developments we follow four or five years later. America is the leader.
He added: “Now I would like to think that in our own little way was the beginning of what going to be a global revolution and Trump’s victory is part of that.”
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The diehard Eurosceptic also said the “revolution” will continue across the crumbling European Union.
He continued: “I am proud to have played my part not just in Brexit but in helping this man become the 45th President of the United States of America.”