Superstar Beyonce helped U.S. First Lady Michelle Obama celebrate her 50th birthday in style by staging a special performance at the White House on Saturday night (18Jan14). President Barack Obama's wife hit the age milestone on Friday (17Jan14) and they marked the occasion with a big party at the White House on Saturday, when guests including musicians Stevie Wonder, Smokey Robinson, Herbie Hancock, Mary J. Blige and Gladys Knight, actor Samuel L. Jackson and basketball legend Earvin 'Magic' Johnson danced the night away to sets by Beyonce, John Legend and Jennifer Hudson. Speaking to reporters at the end of the bash, Robinson said, "We were here for the First Lady's birthday and that was the highlight, and the president gave a wonderful, wonderful speech about her, and then Beyonce performed and wow." The Crazy In Love hitmaker shared a few photos from her White House engagement on her Tumblr.com blog on Sunday (19Jan14), with one image showing the singer in a gold mini-dress as she sits beside the Obamas' pet pooch, Sunny, and another depicting her two-year-old daughter Blue Ivy petting the dog. Beyonce and her rapper husband Jay Z have grown close to the Obamas in recent years - the beauty performed at the President's first inaugural ball in 2009 and at his swearing-in ceremony at the Capitol last year (13). She has also worked with Michelle on her Let's Move campaign against childhood obesity since 2011, reworking the lyrics to her hit Get Me Bodied to encourage kids to get on their feet and get exercising.