Downing Street has tweeted this photograph of the Prime Minister speaking to US President Barack Obama.
Mr Cameron congratulated him on his recent election victory and spoke about the "outstanding relationship" the UK and US share.
Twins in Kenya born on US election day have been named Barack Obama and Mitt Romney.
Mother Millicent Awuor, 20, gave birth in a hospital near the President's father's rural village and named the older boy after the Democrat and the younger after the Republican challenger.
Obama is highly popular in the east African nation and had a beer named "president" in his honour after the 2008 election.
The name Barack means blessed while Obama was the given name of his great-grandfather.
Barack Obama will make a state visit to Burma this month, a Burmese government official reportedly told The Associated Press.
The official said the visit is scheduled for 18 or 19 November and the US President would meet opposition leader Aung San Suu Kyi and government officials, AP reported.
The newly re-elected Obama would be the first US President to visit the country.
Votes in Florida, a state with 29 electoral registers, are still being counted, including absentee ballots.
On Tuesday President Obama won 303 electoral college votes to Republican Mitt Romney's 206, helping him past the 270-vote winning post first.
President Obama has arrived back in Washington DC with his family to begin his second term in office.
The US President will tackle a looming budget crisis and work with Republicans in Congress, the Party which retained control of the House of Representatives on Tuesday, but failed to take the Senate.
From fiscal cliffs and trillion dollar debts to the threat of Iran, ITV News's Mark Austin outlines the issues facing the re-elected US President as he embarks on his final four years in office: