Prime Minister Theresa May will trigger formal negotiations on Britain leaving the European Union on March 29, the British government said on Monday.
It said Britain's envoy to the EU, Tim Barrow, had informed European Council President Donald Tusk's office that May plans to inform the council by letter that she is triggering Article 50 of the Lisbon Treaty, which allows a nation to leave the EU after up to two years of negotiations.
European Commission spokesman Margaritis Schinas confirmed that the commission had been informed in advance of the plan to trigger Article 50.
"We are ready to begin negotiations. We are waiting for the letter - now we know that it will come on the 29th [of March]," Schinas said.
The first step after the receipt of the official notification will be the convening of an EU summit to adopt guidelines for the negotiations.
Brexit Secretary David Davis said May's Conservative government was ready to deliver on British voters' "historic decision to leave the EU" in a referendum in June.
"We are on the threshold of the most important negotiation for this country for a generation," Davis said in a statement.
He said the government wants to agree to a Brexit deal that "works for every nation and region of the UK and indeed for all of Europe - a new, positive partnership between the UK and our friends and allies in the European Union."
The British parliament backed May's Article 50 plan last week, after six weeks of debate during which lawmakers backed down on two amendments.
Speaking during a visit to Wales on Monday, May said she wanted to use Brexit to "strengthen and sustain" the country.
"I have also been clear that, as we leave the European Union, I will work to deliver a deal that works for the whole of the UK," she said.
"I want every part of the United Kingdom to be able to make the most of the opportunities ahead and for Welsh businesses to benefit from the freest possible trade as part of a global trading nation."