French President Francois Hollande declined to answer when asked whether he was "still" having an affair with actress Julie Gayet.
The Daily Telegraph's Senior Political Correspondent Christopher Hope asked the President: "Do you think your private life has made France an international joke? Are you still having an affair with Julie Gayet? And do you wish she was here?"
The build-up to today's Anglo-French summit was dominated by allegations about Mr Hollande's private life.
David Cameron and French President Francois Hollande visited a local pub in the Prime Minister's constituency after they held talks nearby.
Defence Secretary Philip Hammond said Britain and France are "natural partners for defence co-operation" after the Prime Minister announced a series of deals.
Mr Hammond said in a statement:
We have made substantial progress since the Lancaster House Treaty was signed in 2010 and today we have committed ourselves to go further still.
The agreements we have reached at this Summit will improve the inter-operability of our forces, enhance our joint equipment procurement and build on our capacity to support security and stability in places such as Libya, Mali and the Central African Republic.
ITV News Europe Editor James Mates is at the press conference in Oxfordshire:
Inevitably it's left to a UK journalist to ask Hollande 'are you still having an affair with Julie Gayet, do you wish she was here?'
Hollande studiously ignores the question. Talks about European treaty change instead.
David Cameron and Francois Hollande have agreed to extend defence and nuclear co-operation between the UK and France.
The Prime Minister announced a two-year £120 million feasibility study for a new armed drone, called the Future Air Combat System, saying the two countries will work together on the unmanned craft.
He said Britain will offer more logistical support for the French military mission in the war-torn Central African Republic, and announced troops will hold a joint training exercise later in the year.
The UK will try out the French VBCI tank with a view to possibly purchasing it for the Army, he added.
French President Francois Hollande confirmed a £16 billion deal enabling EDF Energy and its British partners to build at least two new nuclear reactors.
Mr Hollande said this would create "thousands of jobs both in the UK and France."
Prime Minister David Cameron said the UK's partnership with France was "as close and important as ever".
Speaking during a news conference with French President Francois Hollande, Mr Cameron said, "We are two leaders determined to keep our citizens safe and to secure a better future for them all."
He described the RAF Brize Norton air base where addressed reporters as "a great example of the close relationship between our two countries".
I've been meeting with President Hollande - discussing the many areas where the UK & France can and do work together. http://t.co/MXemsVwoga
French President Francois Hollande was given a ceremonial arrival at RAF Brize Norton ahead of his summit with David Cameron.