Kourtney Kardashian just can't stop showing off her amazing body.

The 36-year-old mother-of-three flaunted her super slim physique at Hollywood hot spot The Nice Guy on Monday night, wearing a head-turning see-through bra top. Kourtney paired the racy attire with black trousers and a classic blazer, completing her all-black look with a choker and simple heels.

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Kourtney was with her younger sister, 20-year-old Kendall Jenner, who also stunned on the sisters' night out. The model showed off her super tiny waist in a cropped sweatshirt and black trousers, sporting snakeskin-print heels.

A source tells ET the girls’ night out was actually for Cody Simpson’s 19th birthday. “They were there for a little over an hour,” the source says, noting everyone seemed “pretty relaxed.” “Kourtney had some cocktails, while the other girls did not. They did order a few lite bites though.”

Kourtney's certainly been on a roll lately with her super stylish looks, including this silver strapless Julien Macdonald dress she wore to the InStyle and Warner Bros. Golden Globes after-party on Sunday night. Her date to the big bash was her younger sister, 18-year-old Kylie Jenner, who went for a more dramatic look in a sparkly La Bourjoisie crop top and matching skirt.

And check out Kourtney's flawless skin that night.