ABC New's Sunlen Miller reports: To mark the two-year anniversary of her husband’s inauguration, First Lady Michelle Obama surprised visitors on White House tours this morning. “Surprise,” Mrs. Obama exclaimed to guests as they made their way from the Green Room to the Blue Room where the First Lady waited for them. “Every now and then I like to come down and say hello.” The First Lady’s office says that visitors were not aware that Mrs. Obama would be on their tour today – they had the free tickets well in advance – and stumbled upon Mrs. Obama standing in the Blue Room waiting for them on the tour. “I am Michelle Obama. You are in my home,” Mrs. Obama said. “Welcome to my house.” First Dog Bo Obama stayed at Mrs. Obama’s side while the line of people filtered though the Blue Room. “Hug me and pet Bo,” Mrs. Obama said, encouraging people to spend some time with her dog. But Bo got to know one little boy maybe a little too much. At eye level with the little boy, Bo licked his face. “You taste delicious,” Mrs. Obama said imagining what Bo might be thinking and then ultimately telling her dog to stop. As the guests came into the room, Mrs. Obama offered handshakes, hugs, and pictures to a few whose birthday is today and one “Flat Stanley” cutout. Mrs. Obama served as an impromptu tour guide of the White House and the city. One guest – holding a large map of the White House – looked confused and Mrs. Obama said that they are currently in the Blue Room – pointing toward the map. Another guest wanted some directions, asking where D.C.'s famous hot dog dive “Ben’s Chili Bowl” is in the city. “U Street,” Mrs. Obama answered. “They will know,” she added pointing to her aides for a more exact address. Many student groups came in, and Mrs. Obama asked one teenager, wearing a baseball hat backwards, if he was staying out of trouble. “No,” he answered outright. “Okay, alright. At least you’re honest,” she responded with a laugh. At one point there was a break in the stream of people coming into the Blue Room – leaving Mrs. Obama and Bo Obama staring at each other. “I know, you are bored,” Mrs. Obama said to Bo before the next round of people came into the room. The small chit-chat with some of the guests provided a small window into the Obama’s lives. Mrs. Obama is apparently losing her voice after last night’s state dinner. Sasha Obama sprained her ankle playing basketball the other day. And as a Green Bay Packers fan came into the room she waved her hands in the air to block view of the man’s Packers gear and later yelled “Go Bears” after him. Two years ago Mr. and Mrs. Obama greeted White House tours on the president’s first full day in office. Since that time, the White House says over 1.5 million visitors have walked through the gates of their home, “marking the largest attending post 9/11,” the First Lady’s office says.