Indie-rock band The National took to Twitter to announce that they'll be appearing with President Barack Obama at a rally September 1st in Des Moines, Iowa. They tweeted: "Proud to support @BarackObama again in 2012. We'll be opening for him in Des Moines on Sept 1. Follow @OFA_IA for details. #fourmoreyears.".

Pete Wentz worked hard to garner support for Obama's original campaign and shows no sign of slacking now that it's time for reelection. He appeared at an Obama For America rally a few weeks ago, and is going to launch a door-to-door canvassing effort in Bay Village. Not bad.

Mariah Carey went above and beyond by writing a song specifically for Barack Obama without even being commissioned. The track is titled 'Bring It Home' and was performed at a special Obama fundraiser at New York City’s Plaza Hotel last week.

Lady Gaga has never made a secret for her support for Obama. After Obama's support for gay marriage, the 'Born This Way' star tweeted: "Obama, congratulations on being the first sitting President to support marriage equality. Feels like the future, and not the past." She's also been present at his fundraisers.

Bon Jovi not only performed at one of the fundraisers but also seems to be pretty close to the President, seeing as Jon Bon Jovi was snapped getting off the President's personal jumbo jet at JFK airport. Nice work if you can get it.

Joel Madden from Good Charlotte spoke to students in North Carolina encouraging them to vote for Obama. Madden asked them to 'turn their state blue' and also turned up to a fundraiser with wife Nicole Richie in tow.

Jason Mraz is yet another star to lend his musical talents to the Obama campaign. Mraz also performed at a fundraiser, and recently met with some of Obama's staff, posting a photo on his Twitter of himself in an Obama 2012 t-shirt.

Gwen Stefani hosted a 'family friendly' fundraiser at her home, attended by Michelle Obama. Stefani referred to it as a 'playdate' as most celebrities showed up with their children, and the event was attended by 400 people. With a ticket price of $2500, we'll have to pass on this one.

Dave Grohl said in an interview that not only does Obama "have soul," but that he'll definitely be backing him for a second term in the White House. Speaking to Red Bull magazine Red Bulletin, Grohl added: "He's got the toughest job on earth," before proffering his fears on a Republican rule, admitting "I would hate to hand the administration over to another party that is just focused on corporation, greed and money. You know, I'm a fun, peace loving guy, but sometimes the right wing gets a little too selfish."

Cyndi Lauper doesn't do subtle - the star took straight to her website to announce her support for Obama. In a statement posted, Lauper wrote: "President Obama continues to be a true leader for equality and I have never been prouder to call him my president than I am today. The president’s support of marriage equality gives hope and encouragement to the millions of lesbian, gay, bisexual and transgender young people who feel ostracized and alone. The words of the president have reinforced that they are worthy of dignity, respect, and love – just like everyone else."

Even Adam Levine supports Obama - albeit in his trademark obnoxious fashion. The Maroon 5 frontman wrote on Twitter: "thank you @BarackObama for reminding us all that true leadership is not dead." He followed it up with the classy remark: "Dear America, if you don't re-elect @BarackObama, I'm gonna lose my s**t." Lovely.

Cher recently took part in an anti-Mitt Romney video with American comedian Kathy Griffin. She encouraged voters not to vote Republican as they would 'turn back time' on women's rights.

Beyonce wrote an open letter on her website to Obama, labelling him 'inspiring' and commending his 'heart and character'. She added, "You are the leader to take us from where we are to where we need to be."

Jay-Z performed at President Obama's rally in Columbia, Ohio on Monday and changed the lyrics of his famous '99 Problems' song, singing instead, "I got 99 problems, but Mitt ain't one."

Katy Perry showed support for Obama in a rubber voting dress when she performed at a rally. She wore a quirky latex dress which was designed to look like a ballot paper, with Obama's box filled in.

Madonna was booed at a concert in New Orleans for talking about her Obama support - with some fans even leaving the gig completely. Mid-way through her set the singer said: "Who's registered to vote? I don't care who you vote for as long as you vote for Obama."

Paul McCartney posted a video endorsing Obama, with the American members of his band saying that they'd already voted for Obama. The famous Beatle said, "Tell all your friends, get all your mates. Let's get him back into office. Mr. Obama. Vote Obama."

Win Butler of Arcade Fire posted an entire essay supporting Obama on the 90 Days, 90 Reasons website. The singer mentioned, "I want four more sweet years of Canadians liking Americans."