President Obama has pledged that the special relationship between the US and the UK will "grow stronger with time" in spite of Britain voting to leave the EU.
Prior to the referendum in June, the US president said that the UK would be at "the back of the queue" for a trade deal, if it voted to leave the trading bloc.
And at the G20 summit on Sunday, Obama warned that Washington's focus would be on the US-EU trade deal and the Trans-Pacific Partnership.
But speaking with Prime Minister Theresa May, Obama said ties between the two countries could grow even stronger and that the US would work with Britain when it exits the EU.
"We will consult and co-ordinate with her as she and her government move forward with the Brexit negotiations to ensure that we don't see any adverse effects in trading and commercial relationships between the United States and the United Kingdom", said.
He addd: "Even as the UK pursues an orderly exit from the EU, together we reaffirm the very special relationship between the United States and the United Kingdom.
"It will not simply endure, but it will continue to grow stronger with time. The vibrant economic partnership between our countries will continue, as the UK gains further clarity on its new relationship with the EU."
Mrs May was equally complimentary, calling the US a "special partner" for the UK, a "long-standing ally and close friend."
Speaking about their discussions over Brexit, and how that might impact on relations between the two countries, she said: "The UK has always been a strong partner for the US and that will remain the case."
Mrs May added: "As we forge a new global role for the UK we can and will seize the opportunities that Brexit presents and make a success of it."