Donald Trump now believes Brexit is just “an incident” and not part of a wider trend of desertion, according to European Council president Donald Tusk.
But Mr Tusk said: “I was positively surprised by President Trump’s comments on Brexit because it was clear for both of us that in fact the EU as 27 is more united after Brexit than before Brexit and it was also his opinion.
“I tried to convince him and I deeply believe in this that Brexit is very important and dramatic but just an incident not a trend and President Trump agreed. It was for me a very positive moment during our discussions.”
EU officials believe Mr Trump has come to appreciate the value of European integration to US interests since taking office.
And bolstered by the apparent support from the White House, European Commission President Jean-Claude Juncker boasted the EU is the only stable element as Donald Trump, Emmanuel Macron, Paolo Gentiloni and Theresa May prepare for their first G7 meeting.
Seizing the opportunity to push forward his EU agenda and take advantage of his prior G7 experience, Mr Juncker said: “There are four new leaders around the table. We are the only stable elements on the international landscape.”
“We are veterans but we are not old. it will be very interesting.”
The G7 is made up of some of the wealthiest countries in the world – Canada, France, Germany, Italy, Japan, Britain and the US.
Mr Trump and Mrs May are set to hold a meeting at the G7 summit in Sicily amid a row over US leaks about the Manchester bombing investigation.
Sources say the British government is “furious” over the leaks which has seen US officials release details including the bomber’s name and graphic photos of the crime scene before British authorities.
The leaks prompted Greater Manchester Police to temporarily withold information from the US on the investigation.
The New York Times has defended its decision to publish crime scene photographs of the Manchester bombing, saying that the “images and information presented were neither graphic nor disrespectful of victims”.
The row – which goes to the heart of the close intelligence-sharing relationship between the transatlantic allies – provides an awkward backdrop to the Prime Minister’s meeting with President Trump.