
San Francisco 49ers quarterback Colin Kaepernick tweeted this photo as he and First Lady Michelle Obama performing his signature touchdown pose, known as "Kaepernicking." (Instagram/Colin Kaepernick)

San Francisco 49ers quarterback Colin Kaepernick tweeted this photo as he and First Lady Michelle Obama performing his signature touchdown pose, known as "Kaepernicking." (Instagram/Colin Kaepernick)

** FILE ** First lady Michelle Obama speaks during a bill signing ceremony for Maryland's Veterans Full Employment Act of 2013 at the Maryland State House in Annapolis on April 17, 2013. (Associated Press)

** FILE ** First lady Michelle Obama speaks during a visit to Chapel Hill, N.C., on Oct. 16, 2012. (AP Photo/Gerry Broome)

Late-night television host and comedian Conan O'Brien (from left); first lady Michelle Obama; Michael Clemente, executive vice president of Fox News; and President Obama attend the White House Correspondents' Association Dinner at the Washington Hilton Hotel on Saturday, April 27, 2013, in Washington. (AP Photo/Carolyn Kaster)

First lady Michelle Obama and late-night television host and comedian Conan O'Brien gesture toward his tie at the White House Correspondents' Association Dinner at the Washington Hilton Hotel on Saturday, April 27, 2013, in Washington. (AP Photo/Carolyn Kaster)

Late-night television host Conan O'Brien, from left, first lady Michelle Obama, Michael Clemente, executive vice president of Fox News, and President Barack Obama attend the White House Correspondents' Association Dinner at the Washington Hilton Hotel, Saturday, April 27, 2013, in Washington. (AP Photo/Carolyn Kaster)

Christi Parsons, White House correspondent for the Chicago Tribune, Los Angeles Times and Tribune newspaper chain, from left, Chief of Staff Gen. Raymond T. Odierno, Michael Scherer, White House correspondent for TIME, late-night television host Conan O'Brien and first lady Michelle Obama attend the White House Correspondents' Association Dinner at the Washington Hilton Hotel, Saturday, April 27, 2013, in Washington. (AP Photo/Carolyn Kaster)

President Obama and first lady Michelle Obama bow their heads behind a photo of volunteer firefighter Capt. Cyrus Adam Reed, who was killed, at Thursday's memorial service for victims of last week's fertilizer plant explosion in West, Texas.