Donald Trump has pledged to secure a rapid trade agreement with Britain as he predicted leaving the European Union would be a "great thing" for the UK.
In an interview for The Times, the US president-elect said people voted for Brexit because they "want their own identity".
He also used the interview to signal his desire for a new arms reduction agreement with Russia saying the numbers of nuclear weapons should be "reduced very substantially".
In contrast to Barack Obama, who said Britain would be at the "back of the queue" when it came to a trade deal with the US, Mr Trump made clear it would be a priority for his administration.
"We're gonna work very hard to get it done quickly and done properly. Good for both sides," he said.
He made clear that - unlike his predecessor who urged British voters to back Remain - he welcomed last June's referendum vote.
"People, countries want their own identity and the UK wanted its own identity," he said. "Brexit is going to end up being a great thing."
Despite having prompted fears of a new arms race last year when he said the US needed to "greatly strengthen and expand" its nuclear capability, Mr Trump indicated he would like to strike a new nuclear deal with Russia.
"For one thing, I think nuclear weapons should be way down and reduced very substantially, that's part of it," he said.
The president-elect - who will be inaugurated on Friday - also spoke of his belief that German chancellor Angela Merkel had made an error when she opened Germany's doors to migrants.
"I think she made one very catastrophic mistake and that was taking all of these illegals," he said.