Khloé Kardashian and Tristan Thompson Celebrate Son's Third Birthday — See Photos

The famous exes gave fans a glimpse into their youngest child's milestone celebration, which was attended by family and friends. See photos from the joint birthday event.

Khloé Kardashian took to her Instagram Story and shared a series of pictures and videos to mark her son Tatum Thompson's birthday, whom she shares with Tristan Thompson.

One clip shows the outdoor setting decorated with balloons, featuring mascots at the entryway. Another video displays the birthday boy posing with the Mickey mascot at his Mickey Mouse Clubhouse-themed birthday bash.

In one shot, the youngster was pictured with the Donald and Daisy mascots outside. His mother also showed off his three-tier Mickey Mouse theme cake with his name written on it.

The "Keeping Up with the Kardashians" star explained that it was a joint birthday celebration with Amari Thompson, the basketball player's younger brother, and that there were two birthday cakes for the event.

In another video from the backyard celebration, Kardashian showed her son playing with figurines while wearing an apron and asked him whether he was happy. He replied, "Yes." And she responded, "Oh, good."

One other clip showed him dancing with his older sister and cousin, Dream Kardashian. The Good American founder is a mother of two. In addition to her son, she and Tristan also share a daughter, True Thompson.