On Sunday, the Kardashian family celebrated the adorable duo's birthday with a joint bash, featuring a festive "Merry Monster Mash" theme. Saint turns two years old on Dec. 5, while Reign turns three on Dec. 14.
Kim Kardashian West shared cute pics from the day on Snapchat, including this one of their Monsters, Inc.-inspired cakes.
The day's activities included ice skating and sledding.
Santa also made an appearance!
One of the cutest snaps was Kim's husband, Kanye West, leading his son into the rink.
Interestingly enough, Reign's big brother, Mason, also shares a Dec. 14 birthday -- turning eight years old this year -- though presumably, Mason will be having his own special celebration!