Talk about a body revolution.

Lady Gaga wasn't shy about flaunting her body Monday night at the L'Archiduc Jazz bar in Brussels, where she ditched her bra and made sure everyone knew it by sporting a totally sheer black maxi dress.

Wearing a black curly wig, Gaga, 28, confidently hit the streets with her golden underwear also visible.

PHOTOS: Celebs in Their Underwear

Gaga was out celebrating her new jazz album with Tony Bennett titled Cheek to Cheek Monday night, which was released on September 23.

"Popping Champagne and counting down till #CheekToCheek Me, Starlight, my trumpet player Brian, Steve on Sax. We've been friends for almost ten years, and boy have these Rivington Rebels come far. Our ?? still burning strong, while we basque in the glow of legendary Mr. Tony Bennett," she posted on Instagram.

Gaga's revealing dress comes after she hit back at those criticizing her weight on social media earlier this month.

"#bodyrevolution Proud at any size, because the inside is what really counts. Plus, it's all how you pose! Just ask the supermodels," she wrote alongside this picture of her posing in a nude bodysuit.

"I'd rather be fat than shallow," she also tweeted.

NEWS: Lady Gaga Fights Back Against Her Weight Gain Critics

Check out Gaga celebrating another music legend -- Carole King -- in the video below.

Related stories on Hough Gets Nearly Naked on 'Dancing with the Stars'

Just Like Mom: Zoe Kravitz Rocks Lisa Bonet's Signature Dreadlocks