Just in time for the GOP convention at which Mitt Romney will be formally nominated to take on President Obama in November…

The president’s re-election campaign has released a new TV ad in which former President Bill Clinton endorses the administration’s approach to boosting the economy – an issue voters say tops their lists of concerns this election season.

In the ad, Clinton says Obama is the “clear choice” to bring the US back to “full employment” and insists “we need to keep going with his plan.”

He doesn’t mentioned Romney by name, but says the GOP’s policies of cutting taxes on the rich and deregulation are “what got us in trouble in the first place.”

Clinton says Obama’s proposals to strengthen the middle class will eventually put the economy back on track, adding: “That’s what happened when I was president.”

The ad will air in a handful of key states: New Hampshire, Virginia, North Carolina, Florida, Ohio, Iowa, Colorado, Nevada.

Clinton will also be speaking at the Democratic convention in Charlotte, NC.