Kourtney Kardashian. Picture: Instagram

Reality TV star Kourtney Kardashian has revealed she threw up "four or five times" during her post-birthday celebrations.

The reality TV star – who turned 38 on April 18 – has admitted to over-indulging on alcohol during a belated birthday bash in Mexico, where she is currently on vacation with her friends and sister Kim.

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Kourtney wrote on Twitter:

Meanwhile, the brunette beauty – who has Mason, seven, Penelope, four, and two-year-old son Reign with her ex-boyfriend Scott Disick – was wished a happy birthday by various family members last week, including her mother Kris Jenner.

The showbiz matriarch wrote on Instagram:

Elsewhere, Kim wrote on her own website: "Happy Birthday to the best older sister. I'm so blessed to have you in my life. I love how close we were growing up – and still are today. I don't know what I would do without you! Love you!"

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Kim also took to Twitter to mark the occasion, writing:

Meanwhile, Kourtney's half-sister Kendall Jenner also sent her best wishes.

Writing on her website, the 21-year-old model said: "I hope you have the best birthday, Kourtney!!! You do so much for everyone else, so I hope you take the day to treat yourself. I love you! (sic)"