Kourtney Kardashian has just given birth to her third child, her second son, with her long-time boyfriend, Scott Disick, on Sunday. Coincidentally, it was also the fifth birthday of her other son, Mason Dash.

With two birthdays to celebrate, party planning has just gotten a tad bit more interesting for the Kardashian/Jenner clan. Still, Mason had nothing to worry about with regards to his birthday celebration. This will be his last solo birthday party, and it was amazing.

It was a "Nightmare Before Christmas" themed bash, which according to People, was held in advance in November.

Kourtney is the eldest sister in the internationally famous family that is featured in the hit reality TV show, "Keeping Up with the Kardashians." She is followed by Kanye West's wife, Kim, and Lamar Odom's estranged wife, Khloe.

Her second child with Disick, the amazingly adorable Penelope Scotland is two years old.

The 35-year-old Kourtney had actually previously announced that she was going to be welcoming another baby boy soon during "Kourtney and Khloe Take the Hamptons" episode that was aired on TV last week. She said, "It's going to be perfect for our family."

Since Kourtney was giving birth in the hospital, her younger sister, the 34-year-old Kim Kardashian, opted to take Mason Dash out on his special day instead. She shared some cute pictures of herself with her daughter North, Mason Dash, and Penelope Scotland as they went to watch Disney on Ice. She also posted a picture of the kids all holding hands.

The beautiful Mrs. West wrote, "Disney on Ice #Mason #Zeplin #Penelope #North #BestFriends." For the group photo, she captioned it with, "This was an adventure! Try getting 5 kids to look and smile #DisneyOnIce."

A tipster told Us Weekly, "Mason and Penelope had big bags of cotton candy. They seem like an adorable family."