Barack and Michelle Obama surprise White House tour groups Tuesday

Some lucky visitors to the White House Tuesday are in for a surprise.

First lady Michelle Obama revealed on Twitter that she and the president are personally surprising unsuspecting visitors to the White House:

People tuning in to the live stream will find the first couple holding somewhat of a receiving line for tour groups. Some groups have also had interactions with the president's dog, Bo. "He just doesn't know where to sit," Michelle Obama explained to one guest.

"Have fun this week!" the president said to one visitor from out of town.