Prime Minister David Cameron and Pakistan's President Asif Ali Zardari are meeting for an informal dinner amid continuing diplomatic tensions.
Their meeting at the prime minister's Chequers country retreat comes the day before formal talks between the two.
Officials hope the strain caused by Mr Cameron's recent comments - that elements in Pakistan were promoting terrorism - will begin to ease.
President Zardari has also held talks with three other ministers.
No details have yet been released about those meetings - with Conservative Party chairman Baroness Warsi, Home Secretary Theresa May and Education Secretary Michael Gove.
Ahead of the leaders' meeting, a Downing Street spokesman said: "The prime minister is looking forward to welcoming President Zardari to Chequers tonight and tomorrow morning.
"It is an important opportunity to reinforce the strong links between the UK and Pakistan and continue to support stability, security, democracy and prosperity in Pakistan."
The spokesman said the formal talks on Friday were set to cover the floods in Pakistan "and what more the UK can do to help", as well as "co-operation in countering terrorism and violent extremism" and the "next steps in the military surge and political process" in Afghanistan.
The president's visit to Europe comes despite calls to cancel because of Mr Cameron's comments in India last week that some elements in Pakistan "looked both ways" when it came to the Taliban, and also the devastating floods in north-western Pakistan.
Ahead of his meeting with Mr Cameron, President Zardari told the French newspaper Le Monde that the international community was losing the battle against the Taliban in Afghanistan "because we have lost the battle for hearts and minds".
"It is unfortunate that certain individuals continue to express doubts and fears about our determination to fight militants to the end," Mr Zardari said in a statement released before visiting the French foreign minister.
"The war against terrorism must unite us and not oppose us. I will explain face-to-face that it is my country that is paying the highest price in human life for this war."
The PM's comments on Pakistan led to his effigy being burned in the streets of Karachi, and to Pakistani intelligence officials cancelling a visit to the UK in protest.
Mr Cameron has since defended his claim that Pakistan must not "promote the export of terror", insisting the UK-Pakistan relationship was "strong".
"But there has been and still is a problem of terror groups in Pakistan that threaten other countries," he told BBC WM on Tuesday. "[They] also threaten our troops in Afghanistan, threaten India and threaten us in the UK, and they need to be dealt with.
"As I said in India, to be fair to the Pakistan government they have done more recently to combat these terror groups, but they need to go on doing even more, and we should be working with them in order to encourage them to do that."