The first lady, along with dog Bo, is greeting visitors who are taking public tours of the White House on Thursday.
Her anniversary appearance is becoming a tradition - she also greeted tour groups last January, on the one-year mark of Barack Obama's inauguration.
The first lady's office says the appearance is part of her efforts to open up the White House to the public. Her office says 1.5 million people have visited the White House since the 2009 inauguration.
