Hot mama! Kourtney Kardashian showcases toned abs in black bandeau with skin-tight leather trousers as she heads to sister Kylie's Galore party in New York

She has whipped herself back into fantastic shape after the birth of her third child, son Reign Disick back in December.

And Kourtney Kardashian wasn't shy to show off the result of all her hard work.

The 36-year-old reality star flaunted her washboard abs while heading to dinner with her younger sister Khloe in New York City on Monday evening to celebrate their youngest half-sister's Galore magazine cover as part of Mercedes-Benz Fashion Week.

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Hot mama! Kourtney Kardashian was spotted leaving her hotel heading to her half-sister Kylie Jenner's Galore magazine cover in New York City on Monday night 

Hot mama! Kourtney Kardashian was spotted leaving her hotel heading to her half-sister Kylie Jenner's Galore magazine cover in New York City on Monday night 

Kourtney looked stylish head-to-toe black as she headed from her hotel in the Big Apple for a night out at popular club Up & Down for her youngest sibling Kylie Jenner's big night.

The eldest of the three Kardashian sisters looked in fine form as she showed off her toned tummy in a black bandeau with matching high-waisted leather trousers.

The mother-of-three flaunted her taut midriff - complete with hard-earned definition - with pride, while also making a stunning showing of her slim and shapely pins. 

The single star - who split from long-term boyfriend Scott Disick earlier this year - also sported a pair of strappy black heels with a metallic gold detailing and accessorised with a small, black leather designer purse

Ab-solutely stunning: Kourtney flaunted her toned abs in a black bandeau for the occasion, her middle notably toned after working hard following the birth of her youngest child
Ab-solutely stunning: Kourtney flaunted her toned abs in a black bandeau for the occasion, her middle notably toned after working hard following the birth of her youngest child

Ab-solutely stunning: Kourtney flaunted her toned abs in a black bandeau for the occasion, her middle notably toned after working hard following the birth of her youngest child

Good spirits: The 36-year-old - who is almost inexplicably youthful - flashed a smile as she covered up in a black satin bomber jacket

Good spirits: The 36-year-old - who is almost inexplicably youthful - flashed a smile as she covered up in a black satin bomber jacket

Rocking out: She also sported a pair of high-wasited black leather trousers with strappy black heels

Rocking out: She also sported a pair of high-wasited black leather trousers with strappy black heels

Natural beauty: She wore her straight raven-coloured locks down and had natural, complementary make-up on her face

Natural beauty: She wore her straight raven-coloured locks down and had natural, complementary make-up on her face

Despite showing off a bit of skin, she made sure that she was a little bundled up for the Seventy degree weather as she sported a satin bomber jacket.

Her straight raven-coloured locks were worn down as she sported natural, complimentary make-up on her face.

Kourtney is mother to her three children from her relationship to Disick, nine-month-old Reign, Penelope, three, and five-year-old Mason.

Party people: The 36-year-old was joined by her younger sister Khloe for the night out at Up & Down as part of Mercedes-Benz Fashion Week

Party people: The 36-year-old was joined by her younger sister Khloe for the night out at Up & Down as part of Mercedes-Benz Fashion Week

Curvaceous: Khloe, 30, also showed off her fantastic figure for the night on the town

Curvaceous: Khloe, 30, also showed off her fantastic figure for the night on the town

Lovely: She wore a lacy black maxi dress along with matching Christian Louboutin heels
Lovely: She wore a lacy black maxi dress along with matching Christian Louboutin heels

Lovely: She wore a lacy black maxi dress along with matching Christian Louboutin heels

Night out: She put her pucker on full display with shiny pink lipstick as her blonde locks were pulled back in a flowing ponytail

Night out: She put her pucker on full display with shiny pink lipstick as her blonde locks were pulled back in a flowing ponytail

Ready to party: She grabbed on to her small black leather designer bag with a chain strap

Ready to party: She grabbed on to her small black leather designer bag with a chain strap

Khloe also let her curvaceous figure on full-display as she rocked a clinging long-sleeved, lacy black maxi dress which she teamed with black Christian Louboutin stilettos.

Her blonde locks were pulled back as they flowed over her shoulder and she also had complimentary make-up complete with heavy mascara and eyeliner.

The newly-turned 18-year-old star Kylie matched with her sisters in black as she rocked an intricate mini dress featuring a sheer polka dot top and zipper down the middle.

She was joined by her 25-year-old boyfriend Tyga who wore a velour black hoodie with matching trousers and white Vans sneakers.

Woman of the hour: Kylie Jenner arrived to her cover party in style

Woman of the hour: Kylie Jenner arrived to her cover party in style

Interesting look: The newly-turned 18-year-old's dress featured a sheer polka dot top and zipper down the middle
Interesting look: The newly-turned 18-year-old's dress featured a sheer polka dot top and zipper down the middle

Interesting look: The newly-turned 18-year-old's dress featured a sheer polka dot top and zipper down the middle

Comfortable customer: Her 25-year-old rapper boyfriend Tyga wore a velour black hoodie with matching trousers

Comfortable customer: Her 25-year-old rapper boyfriend Tyga wore a velour black hoodie with matching trousers

Also seen heading to the event were Jesse Metcalfe and Cara Santana who arrived in very fashionable looks. 

The racy photos from the magazine featuring Kylie were unveiled last week as they were shot by controversial photographer Terry Richardson. 

Infamous fashion photographer Richardson has denied past allegations that he acted inappropriately towards a number of models he's worked with. 

Msaking appearances: Jesse Metcalfe and girlfriend Cara Santana were among the stars seen heading to the event

Msaking appearances: Jesse Metcalfe and girlfriend Cara Santana were among the stars seen heading to the event

Loved up: The couple walked arm-in-arm as they hit the Big Apple hotspot
Loved up: The couple walked arm-in-arm as they hit the Big Apple hotspot

Loved up: The couple walked arm-in-arm as they hit the Big Apple hotspot

Looking good: The hunky 36-year-old John Tucker Must Die star and his 31-year-old Beverly Hills Chihuahua 3: Viva la Fiesta! girlfriend brought their most stylish looks to the gala

Looking good: The hunky 36-year-old John Tucker Must Die star and his 31-year-old Beverly Hills Chihuahua 3: Viva la Fiesta! girlfriend brought their most stylish looks to the gala

All grown up: Kylie posed for controversial photographer Terry Richardson for the new issue of Galore as the racy photos were revealed last week

All grown up: Kylie posed for controversial photographer Terry Richardson for the new issue of Galore as the racy photos were revealed last week

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