WASHINGTON — Bill Clinton is to sprinkle political stardust on President Barack Obama's re-election bid by giving the nominating address at the Democratic Party convention, the campaign said Monday.

The 65-year-old former president, a hugely popular figure more than 11 years after leaving office, will outline the economic arguments for giving Obama a second term in a speech on September 5 in Charlotte, North Carolina.

"President Clinton oversaw the longest economic expansion in US history, pursuing many of the same policies that president Obama is proposing and implementing today," said 2012 Democratic Convention Chair, Los Angeles Mayor Antonio Villaraigosa.

"That economic progress was squandered in the following decade by a set of decisions that exploded our deficit, crashed our economy, and hurt the middle-class.

"So, there is no one better to lay out the choice in this election between moving forward with president Obama or falling backward with Mitt Romney, who supports the same failed policies that led to the worst economic crisis since the Great Depression."

Obama and Republican challenger Mitt Romney are locked in a neck-and-neck battle for the White House ahead of November 6 elections likely to be dominated by economic concerns weighing heavily on the electorate.

The US economy has grown slowly in recent quarters as much of Europe has slipped backed into recession. Unemployment remains stubbornly high, above eight percent, and Obama has struggled to produce lasting economic momentum.

In American politics, raucous conventions are held a couple of months before polling day at which the rival candidates are formally nominated, and where party grandees, and sometimes rising stars, try to whip up support with stirring speeches.

Clinton addressed the convention four years ago in very different circumstances after his wife, Secretary of State Hillary Clinton, narrowly missed out to Obama for the Democratic nomination.

His address and endorsement of Obama, after being one of his fiercest critics, was seen as a crucial step in unifying the party behind what turned out to be a winning ticket.

Joe Biden will issue the rallying cry on September 6 as the Democrats rekindle an old tradition of having both the vice presidential candidate and the presidential candidate address the final night of the convention.

Biden's speech, before he and the president take the stage together to accept the nomination, will focus on reminding Americans about Obama's first term accomplishments despite the difficult economy, the campaign said.

"As the president's partner, vice president Biden is uniquely positioned to talk about the tough decisions the president has made over the last four years to rebuild the economy after the worst financial crisis since the Great Depression and strengthen our national security," said Villaraigosa.

"He'll give a first-hand testament to the president's focus on doing what is right for the country, not what is politically popular."

Romney's campaign hit back hard at Monday's announcement, saying Obama could hardly pretend to be as fiscally sound as Clinton -- who left office with a budget surplus -- having failed to halt America's ballooning deficit.

"After four years of trillion-dollar deficits and anemic economic growth, it's clear president Obama would love to run on president Clinton's record in office," said campaign spokesman Ryan Williams.

"But no amount of showmanship can paper over the differences between these two presidents. Americans deserve a president willing to run on his own record, not the record he wishes he had."

The Republican Party convention, when Romney will officially be crowned the nominee, is taking place in Tampa Bay, Florida from August 27 to August 30.

Before then, Romney is expected to announce his running-mate. Former Minnesota governor Tim Pawlenty and Rob Portman, a senator from the key swing state of Ohio, are seen as frontrunners.