Neil Patrick Harris and David Burtka Celebrate 'Remarkable' Twins Harper and Gideon's Birthday

Neil Patrick Harris and David Burtka's twins are celebrating their golden birthday.

On Wednesday, Harper Grace and Gideon Scott turned 12 years old, marking the special occasion where they turn the age of their date of birth (Oct. 12).

The Uncoupled star, 49, shared sweet pictures hugging each of his kids on Instagram, along with a heartfelt caption reflecting on the major milestone moment.

"Twelve years old today. Harper and Gideon are, without question, the greatest two things that have ever happened to me," he wrote. "They inspire me, make me chortle, allow me to be an imperfect father, and fill me with a type of love I never knew could exist."

Noting that parenting is "all-consuming" and "the most constantly challenging thing David and I have ever done," the How I Met Your Mother alum expressed that his kids are "so, so worth it."

"They are remarkable. They are my children. They are my world," he shared, adding, "I am supremely proud of who they have become, of who they are becoming, and am just so grateful to have them in my life."

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On his Instagram page, Burtka, 47, shared a photo of the twins posing together. Harper wears black jeans, a bright teal t-shirt and a black leather jacket for an effortlessly cool look while Gideon opts for a white t-shirt with a black smiley face spray-painted on and a pair of jeans.

"Happy 12th GOLDEN Birthday to these incredible kids! I can't believe how fast this has all gone!" the chef wrote. "I am so proud of how you are growing up."

"You are sweet, caring, compassionate, creative and you have the best sense of humor. I am proud to be your dad and I can't wait to see how the next 12 years evolve," he continued.

"I couldn't ask for better kids! #goldenbirthday#12on12"

During an appearance on The Tonight Show earlier this summer, the Broadway actor opened up about his kids' interests.

While Gideon is into gaming, Harris said Harper has a newfound love of horror movies that the actor isn't sure he should be embracing.

"What do you say to a girl who wants to watch horror movies?" he asked. "Do you say 'Absolutely not?' Because then she wants to watch them more."

After watching It and Stranger Things, Harper wanted to know the scariest movie Harris had ever seen. He was reluctant to offer an answer, knowing she'd want to watch whatever he replied with. The tween eventually wore him down and his response was The Shining, so she asked to watch it.

When the movie was over Harris asked Harper her thoughts on the film, to which he was surprised to hear her say, "I'm mildly disappointed," followed by, "That's the scariest movie you've ever seen?"

Though she played it cool, Harris did admit that Harper "has slept in our bed for like the last four nights."