Kourtney, Kim and Khloe Celebrate Mason's Third Birthday!

Posted Saturday December 15, 2012 11:07 AM GMT

Headed out for an evening of fun to celebrate their son's third birthday, Kourtney Kardashian and Scott Disick arrived at Serendipity's in Miami on Friday night (December 14).

The 33 year-old mom of two toted in her adorable new daughter, Penelope, while sister Khloe followed closely behind with the fashionable birthday boy in tow.

Also joining in on the family festivities was Aunt Kim, who left a heartwarming message on her Twitter page for her nephew, writing, "I can't believe Mason is turning three today! He has changed my world in so many ways and I am amazed every day by him," she said. "He is the world's greatest big brother to Penelope and the most loving nephew any aunt could ask for. Happy birthday Mase, love Aunt KiKi."

Showing love to her first born, Kourtney took to her Celebuzz page, penning, "Happy Birthday to my most precious angel who has forever changed my heart. I will never forget the day you entered my life, three years ago. It is an honor and a joy to watch you grow every day."

Although southern Florida is only the family's home for a short time while they film "Kourtney and Kim Take Miami," the E! reality star explained to Us Weekly that she will also throw her growing boy a party of his own with all his friends when they return to Los Angeles.