James Van Der Beek Jokes About His 6 Kids' 'Ad-Libbed' Halloween Costumes 'Moments Before Leaving'

James Van Der Beek/Instagram

James Van Der Beek is appreciating his kids' Halloween spirit.

The actor's six kids — daughters Gwendolyn, 4, Emilia, 6, Annabel, 8, and Olivia, 12, and sons Joshua, 10, and Jeremiah, 12 months — celebrated the holiday by dressing up in what he described as "ad-libbed" costumes.

"#Halloween costumes were planned (and changed) all year long, ordered during our RV trip this summer, delivered months in advance, worn until they broke or lost pieces sometime in early September, and then, moments before leaving to trick-or-treat tonight, each kid just ad-libbed with pieces we've collected over the years," the actor wrote.

The Dawson's Creek alum dressed in a mish-mosh of steampunk accessories while wife Kimberly opted for a simple witch look. Van Der Beek held youngest Jeremiah, who was dressed as a newly-hatched dinosaur.

Oldest daughter Olivia wore a black corset dress with fishnet stockings and combat boots, next to Annabel who wore a masquerade mask with a floral dress and elbow-length gloves. Emilia rocked a superhero-toga combination outfit with devil horns, while Gwendolyn was a sheet ghost. Joshua rounded the costumes out with a red mask and an all-black outfit.

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In an Instagram post last week, the father of six talked about getting "SUPER emotional" thinking about "Halloween through the eyes of a child."

"I've been SO busy, so overwhelmed - all with 'important' (and really exciting) stuff - but this family adventure in the midst of a crazy week made me borderline weepy about my kids still being young enough to be enchanted by lights and pumpkins," he wrote.

"Granted, @pumpkinnights was a Texas-sized extravaganza… but in the midst of so much planning and effort to build a solid future for my kids, it was #jackolanterns and spooky music that put me right back in the present… and reminded me nothing is more important."

James Van Der Beek/Instagram

In September, Van Der Beek reflected on his journey as a dad as he celebrated his oldest, daughter Olivia, on her 12th birthday.

"12 years ago today you changed my life in one instant. Literally the second you came out, I went from recognizing that I would have to put someone else's needs first… to wanting nothing more than to reorganize my life to support you and whatever you needed," he wrote.

"You came out perfect. 'Parent-proof' as I like to say. But it's true. And as I watch you tiptoe into adulthood, one priority re-arrangement at a time… I marvel at your grace, your creativity, and the loving kindness you've embodied since day one that continues to bloom in ways that are ever more inspiring more profound."

"In deep gratitude that, of all the hearts you could have commandeered in this infinite universe… you saw fit to invest in mine," he concluded. "I love you kiddo. You've got a fan for life. ❤️"