Rita Ora wardrobe malfunction, Rob Kardashian's ex flashes sexy underwear while celebrating 23rd birthday in London [PHOTOS]

Happy birthday, Rita Ora! Now - show us your panties!

The "How We Do (Party)" songstress just celebrated her 23rd birthday on Tuesday (Nov. 26). In honor of the special occasion, Ora posted this sexy snapshot on Instagram:

ritaora: "Birthday girl!! today I'm allowed to be A F***ING STAR! Thank you everyone for the birthday wishes and I love you!!!!"

That night, Ora partied with her celebrity pals at London's popular nightclub The Box. Kelly Brook, Eve, and Ora's boyfriend Calvin Harris were in attendance. Rob Kardashian's ex looked very retro in a high-slit red velvet dress, fur coat, and killer black Louboutins heels. But what really stole the show was Ora's lacy underwear, which she flashed to cameras while stepping out of her car before entering the club.

The high-slit dress revealed Ora's sexy toned legs... and her dainty undergarments! Hey, at least she didn't go comando! Check out the photo here.

Despite the minor wardrobe malfunction, Ora totally rocked the glamorous look. Happy birthday, girl!

ritaora: "Studio 54....70's The ORA and Devolle way @kyledevolle #itsmyBirthday"