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.
Now Barack Obama has secured four more years in the White House he must tackle the growing list of challenges facing America.
While both parties called for unity in Barack Obama's second term to solve the USA's problems, Mark Austin found voters fearful of gridlock.
Barack Obama has secured re-election as President on a night of drama in America. Here are the best pictures from election night: