As reported by AOL Music, there is a very good reason they call her Queen B. Beyonce stunned last night (March 19) as she headed to the Greenwich Hotel in New York, showing off her incredible post-baby body in a figure-hugging Victoria Beckham dress. The blue ensemble, no doubt an homage to baby Blue Ivy, displayed the new mom's incredible weight loss after giving birth just 10 weeks ago.

Bey was on her way to a fundraiser dinner hosted by First Lady Michelle Obama and Robert DeNiro, when she was snapped by the paparazzi. The diva dined with her mother Tina Knowles and mother-in-law Gloria Carter at the event ... but we're fairly sure from the looks of that teeny-tiny waist, Bey wasn't indulging too much!

We can't wait to see how the hot mama looks in May, when she triumphantly returns to the live stage. Bey announced yesterday she would be making her post-baby comeback with a series of concerts at the Revel Resorts casino in Atlantic City, N.J.!

Watch 'Beyonce Dons Victoria Beckham Dress For Michelle Obama's Fundraiser'
Watch Beyonce's 'Love on Top (Live From Roseland)' Video
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