Michelle Obama at 2015 Black Girls Rock! Event
Credit: Brad Barket/Getty Images

The First Lady's style never seems to fail. Case in point: Michelle Obama’s look from BET's 2015 Black Girls Rock! event on Saturday night, when she wowed with both her ensemble and an inspirational speech. The FLOTUS received a standing ovation as she took the stage, wearing a white off-the-shoulder Zac Posen dress and metallic silver Jimmy Choo pumps.

"To all the young women here tonight, and all across the country, let me say those words again: Black girls rock!" Obama declared. "We rock! We rock! No matter who you are, no matter where you come from, you are beautiful, you are powerful, you are brilliant, you are funny! Let me tell you, I'm so proud of you. My husband, your president, is so proud of you. And we have such big hopes and dreams for every single one of you."

The designer was so excited that he shared an Instagram photo of Obama in the frock, which Posen captioned: "Such an thrill and honor to wake up to the #FirstLady #MichelleObama #FLOTUS wearing #ZacPosen."

Black Girls Rock! is a non-profit youth organization that aims to help and empower young black girls. You can watch Michelle Obama's full speech when the event airs April 5 at 7 p.m. ET on BET.