In advance of the NBC News special "Inside the Obama White House" — set to air tomorrow and Wednesday at 9pmET — Brian Williams tells The Washington Post's Howard Kurtz that among the 150 hours of footage shot for the program, "there's stuff we've never seen of how the White House operates...we were pretty stunned at how much we were able to record and how natural events seemed to be."

Williams talks of "walking through the West Wing and Secretary [Hillary] Clinton drops by to see the president. To be in the hallway when the president walks by with a handful of M&Ms, popping them in his mouth as he goes to visit his chief of staff — it was unbelievable."

"Inside the White House" is part of a forty-year NBC tradition of giving viewers behind-the-scenes insight into a new president's day-to-day life. Kurtz reports that "Williams had to make the sale" to get access, though, "a lobbying effort that began before the election."

Williams also says WH Chief of Staff Rahm Emanuel gave permission for crews to chronicle various meetings of senior staff, although "Rahm closed the door in front of our crew eight times."