Hot mama! Kourtney Kardashian is celebrating her birthday by getting naked on Instagram!

The mother-of-three is stripping down to her birthday suit to ring in her 38th year — and she is looking better than ever.

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Whipping her hair back in a golden pool, Kourtney proves age is nothing but a number as she flaunts her toned booty and a hint of side boob. (Click here to see the photo!)

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o n. m y. a p p.

A post shared by Kourtney Kardashian (@kourtneykardash) on

Taken by celebrity photographer Mike Rosenthal, the brunette beauty definitely surprised her followers with the impromptu nude photo shoot.

“You just slayyyyed my life omfg,” one fan wrote while another added, “After 3 kids and still killing it.”

MORE: Kourtney Kardashian Slammed for Flaunting Wealth on Instagram 5 Months After Kim’s Robbery

It seems Kourt is sending her ex-boyfriend Scott Disick a message with this sexy snap after he was caught sneaking a much-younger model on a family vacation.

kourtney kardashian scott disick kids instagram
Instagram

Kourtney and Scott with kids Mason, Penelope, and Reign.

“Scott’s been hooking up with a young model… He actually flew her to Costa Rica and tried to hide her in his hotel room without the Kardashians knowing,” an insider told In Touch in February. “They went to get him in his room and saw [the model] standing there. Scott immediately panicked and tried to get them out, but it was too late.”

Kourtney, who was recently spotted on what appeared to be a date with Diddy’s 25-year-old son Quincy Combs, is embracing her MILF side.

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“Kourtney has no shame in her game, she’s proud of being a cougar,” a source told Hollywood Life. “Being with younger guys like Quincy and Justin [Bieber] is a huge ego boost.”

The insider continued, “Scott destroyed her self-esteem with his cheating, this is a way for her to build her confidence back up. They make her feel hot and she needs that. There’s no drama or baggage, it’s just easy, sexy, fun.”

Get it, girl! For more celebs who have stripped down on Instagram, click through the gallery below!