President Barack Obama will mark his 51st birthday next month with "a little celebration" at his Chicago home.

First lady Michelle Obama says in a fundraising email to supporters that the campaign is planning a fundraiser at their house in Chicago's Kenwood neighborhood - and grass-roots donors can win a chance to get on the guest list.

Supporters who give $3 or more to Obama's re-election campaign automatically will be entered into the contest to join Obama at the fundraiser.

Mrs. Obama says her husband's birthday will be "one of the last opportunities he'll get for a little downtime before the final weeks of the election."

Obama's birthday is August 4.