text: Mrs May will be the first foreign leader to meet the new president after his inauguration.
  A post-Brexit free trade deal is thought likely to be high on her agenda as she travels to the US for talks.
  Confirmation of the meeting came as hundreds of thousands of people around the world joined women's marches to protest Mr Trump's presidency.
  Mr Trump's press secretary Sean Spicer gave details of Mrs May's visit in his first briefing to journalists at the White House on Saturday.
  Earlier, while visiting the CIA's headquarters, President Trump said the PM "is coming over to our country very shortly".
  Nato, the European Union, defence and Russia are all likely to be discussed in the meeting.
  The BBC's political correspondent Iain Watson said the "symbolism will be very important" and with Brexit negotiations about to get under way, the fact Mrs May will be meeting the new president so soon will be "politically significant".
  Our correspondent said there had been a lot of effort to make sure Mrs May was one of the first leaders President Trump would meet.
  In December the PM's joint chiefs of staff, Nick Timothy and Fiona Hill, travelled to the US to build links with the incoming president's team ahead of his inauguration on 20 January.
  Theresa May congratulates Trump on taking office
  In a statement issued after the inauguration, Mrs May said: "From our conversations to date, I know we are both committed to advancing the special relationship between our two countries and working together for the prosperity and security of people on both sides of the Atlantic.
  "I look forward to discussing these issues and more when we meet in Washington."
  Mrs May has promised to hold "very frank" discussions with Mr Trump.
  She told the Financial Times she believed the new president recognised the importance and significance of Nato and the "importance of the co-operation we have in Europe to ensure our collective defence and collective security".
  On the day after his inauguration, at least 500,000 people gathered for a rally outside the US Capitol building in Washington while organisers said an estimated 100,000 descended on central London on Saturday as similar events were staged in major cities across the US and around the world.
target: Prime Minister Theresa May will meet US President Donald Trump in Washington DC on Friday, the White House has said.