Beyonce had a very special guest in the audience of her second comeback concert in Atlantic City, New Jersey on Saturday (26May12) - First Lady Michelle Obama.

The hitmaker, who has been on a performing hiatus since announcing she was pregnant last year (11), wowed a sold-out crowd at the newly-launched Revel Resort on Friday (25May12) for her first live gig since giving birth to daughter Blue Ivy in January (12).

And on Saturday President Barack Obama's wife and daughters Sasha and Malia traded the White House for a packed concert hall to see their idol, with the trio receiving a warm welcome from the audience as they found their seats.

Beyonce opened the show with End of Time, later singing such tunes as Party, Get Me Bodied, Crazy In Love and Love On Top, which the two young girls sang along to.

A source tells UsMagazine.com, "They sat up in a private balcony with (TV personality) Gayle King. Michelle was jamming out to Crazy in Love. When Beyonce told the crowd to get up and jump, (Malia and Sasha) stood and started dancing and jumping. They were shouting when Beyonce asked, 'Do girls run the world?' Together, all three of them did the 'Single Ladies' dance moves."

Obama and the pop star have developed a close relationship as of late - Beyonce wrote a hand-written letter to the politician earlier this year (12) praising her role model status and she also backed the first lady's anti-childhood obesity campaign, Let's Move!.