Kim Kardashian experienced a major wardrobe malfunction in her black and blue gown before hitting the 2014 Met Gala red carpet with fiance Kanye West on May 5. Credit: AKM-GSI

Uh oh, the underwear is out! Kim Kardashian experienced a major wardrobe malfunction before hitting the Metropolitan Museum of Art's Costume Institute Gala with fiance Kanye West on Monday, May 5.

The reality star, 33, unknowingly flashed her dark underwear after her layered custom-designed Lanvin gown—which included a leg-baring thigh-high slit—exposed her panties from the side. The incident occurred as she left the Lanvin store with West, after getting fitted for her custom-designed look.

Kardashian's leg-baring Lanvin number also included a thick black belt that cinched her increasingly tiny waist. On the red carpet, North West's mommy looked classy and pretty with her glossy brunette locks swept to one side. She also wore a pair of diamond drop earrings by pal, jewelry designer Lorraine Schwartz (who also designed her engagement ring), and rocked black cage sandals by Lanvin.

Kardashian's equally-fashionable beau, 36, rocked a sharp black velvet tuxedo, which included with leather paneling on both sides of his pants. Together, they looked affectionate and sweet on the red carpet.

The couple's second year together on the Met Gala red carpet is a stark contrast from last year's memorable appearance. Kardashian, who was expecting her first child last May, wore a talked-about floral Givenchy gown, which sparked negative commentary from critics.

Kimye's 2014 Met Gala appearance comes a little over one month after their talked-about April 2014 Vogue cover was released. The engaged couple is currently preparing for their upcoming wedding, to be held in Paris, France, in several weeks. Photos: Best Met Gala gowns of all time!

Tell Us: What do you think of their red carpet appearance?