Kourtney Kardashian's sons have "forever changed [her] heart".

Kourtney Kardashian

Kourtney Kardashian

The 'Keeping Up With The Kardashians' beauty took to her Instagram page to wish a happy birthday to her eldest child, Mason, six, and 12-month-old Reign, yesterday (14.12.15).

Captioning a photo of the pair, she wrote: "Happy Birthday to my sweet boys who forever changed my heart! I still can't believe they have the same birthday. (sic)"

The 36-year-old star - who also has daughter Penelope, three with her ex-partner Scott Disick - celebrated the kids' birthdays with a trip to alien laser tag this weekend and was joined by a host of her friends as well as her half-sisters Kendall and Kylie Jenner.

Meanwhile, sister Kim Kardashian West - who recently gave birth to her second child, a son, Saint - previously praised Kourtney's "strength" in the wake of her break up.

She said: "She shared a lot about her relationship with Scott this season [of 'Keeping Up With The Kardashians'] and you get to see their journey.

"She is so strong. She's raising the three kids. It's really hard. Three kids, especially by yourself, has been an adjustment for her. You never thought this cycle would really end of Kourtney and Scott, which was kind of the same thing for 10 years."

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