The former US president Bill Clinton has given a rousing speech supporting Barack Obama to be re-elected.
Clinton said Obama was the best man to lead America and that he would sort out the country's money problems.
Clinton's wife, Hillary, is also a senior politician and works for Obama's government.
Obama will compete with Republican Mitt Romney in November's presidential election.
Clinton was US president from 1993-2001 and was hugely popular, but was heavily criticised for his personal life.
He also helped the peace process in Northern Ireland and reached a deal for peace in the Middle East between Israeli and Palestinian leaders.