Christmas has come early for tens of thousands of federal employees: President Obama has signed an executive order closing executive branch agencies on Christmas Eve.

The White House said Friday that Obama has approved a plan that will give all workers -- except essential employees -- a day away from the office on Monday.

Federal employees were already scheduled to have a holiday on Tuesday.

Christmas Day has been a holiday for all federal employees since 1968, though some classifications of federal workers have been able to take the day since 1870.

The National Taxpayers Union estimates that each federal holiday costs about $450 million, including the effects of lost productivity.