Kim, Kourtney Kardashian Throw Sons Joint Pixar-Themed Birthday Party

Kim and Kourtney Kardashian made sure their sons had double the fun for their birthday this year, throwing an elaborate Monsters Inc.-themed party for Saint West and Reign Disick Sunday.

Kim and husband Kanye West's son Saint turns 2 Tuesday, and Kourtney and ex Scott Disick's son Reign turns 3 on Dec. 14.

The Keeping Up with the Kardashians sisters celebrated the toddlers' birthdays with an epic party complete with an ice rink, fake snow and visit from Santa Claus. Silver balloons spelling out "Merry Monster Mash" completed the birthday decor.

Kim documented the party on her Instagram stories, showing West taking to the ice with his son and 4-year-old daughter North.

monsters inc party

A birthday party isn't complete without cake however, and this is where the Pixar theme really came in.

The two celebrated with elaborate custom cakes showing the Monsters Inc. protagonists Sully and Mike Wazowski.

monsters inc cake

Kim and her husband will soon have another birthday to celebrate.

The couple is expecting their third child via a surrogate, and while Kim had health problems during both of her pregnancies, she revealed that the surrogacy process is actually harder for her.

"You know, it is really different," she said last month. "Anyone that says or thinks it is just the easy way out is just completely wrong. I think it is so much harder to go through it this way, because you are not really in control. And, you know, obviously you pick someone that you completely trust and that you have a good bond and relationship with, but it is still ... knowing that I was able to carry my first two babies and not, you know, my baby now, it's hard for me. So, it's definitely a harder experience than I anticipated just in the control area."

“I hated being pregnant … I thought this was going to be so easy, but you know, even in how much I hated it, if I could do it myself I would have preferred that,” she explained. “So that inner struggle is kind of hard, but I am just rolling with it and it is what it is.”

Keeping Up with the Kardashians airs Sundays at 9 p.m. ET on E!