Japanese Prime Minister Shinzo Abe has told business leaders in Tokyo he has "trust" in the UK economy after Brexit.
Japan's corporate sector has raised concerns about the UK's decision to sever ties with Brussels and the government previously made clear it wanted the country to remain in the bloc.
But speaking via a translator, the premier said Tokyo had received a commitment that there will be transparency and predictability as Britain quits the EU.
The UK will remain a "compelling place", he told a UK Japanese business forum. Mr Abe said: "With the UK leaving the European Union, the UK is in the midst of great change. The UK's departure from the EU has to be successful for the UK, European Union and global economy - this is going to be quite important that this exit is going to be a successful one.
"I have trust in the UK economy after Brexit. Many Japanese companies even after the Brexit vote they have decided on new investments into the United Kingdom. This is testimony to Japanese companies' expectations of the United Kingdom.
"From the UK in the EU exit negotiation, there has to be transparency and predictability to minimise any damage on the businesses. We have received that commitment and we value this greatly. Even after Brexit the UK, for business people, it will continue to be a compelling place. I am convinced of that."
Theresa May told the business group that Japan was one of the key trading opportunities for trade after Brexit.
The Prime Minister said: "This is a formative period in shaping the future of my country and as we leave the European Union, so I am determined that we will seize the opportunity to become an ever more outward-looking global Britain, deepening our trade relations with old friends and new allies around the world. And there are few places where the opportunities of doing so are greater than Japan, the third largest economy in the world.
"So I am here together with a business delegation representing some of Britain's biggest investors in Japan, because we want to build on that momentum, and because I believe this is a good moment for like-minded partners such as Britain and Japan to be doing more together.
"For as we become a global Britain, a European nation still, but one that is outside the EU, so we will be free to engage more actively and independently, particularly in key Asian markets like Japan."