James Van Der Beek is “gutted” to drop out of Monday’s long-awaited “Dawson’s Creek” reunion.

The actor, who went public with his stage 3 colorectal cancer battle in November 2024, explained to his Instagram followers over the weekend that he is “out of commission.”

On Sunday, the “Varsity Blues” star, 48, wrote, “Two stomach viruses conspired to … keep me grounded at the worst possible moment.”

He noted that the charity event, put on in partnership with F Cancer, was the “evening [he’d] been looking forward to most” since Michelle Williams came up with the idea in January.

Van Der Beek and Williams, 45, were set to reunite with Busy Philipps, Katie Holmes, Joshua Jackson and more former co-stars in New York City at the Richard Rodgers Theatre.

“Despite every effort… I won’t get to be there,” Van Der Beek, who played Dawson Leery for six seasons, confirmed. “I won’t get to stand on that stage and thank every soul in the theater for showing up for me, and against cancer, when I needed it most.

“But I DO have an understudy,” he continued. “A ridiculously overqualified replacement who would have been #1 on my wishlist (had I ever dreamed he’d be available). Someone my kids would definitely consider an upgrade over me. Plus, he already knows how to get to the theater. So that’s convenient.”

Lin-Manuel Miranda is taking over for Van Der Beek — a sentence the “Dancing With the Stars” alum couldn’t “believe [he] got to type.”

He gushed, “Thank you @lin_manuel . You were a hero to my kids before … now you’re a demigod 😇.”

Van Der Beek concluded, “Everyone please enjoy all the love in that room. Shine some on my family. I will be beaming and receiving from afar in a bed in Austin.”

The “Rules of Attraction” star’s wife, Kimberly Van Der Beek, will be in attendance with their six children — Olivia, 14, Joshua, 13, Annabel, 11, Emilia, 9, Gwendolyn, 7, and Jeremiah, 3.

“Was important to him we come!!” the 43-year-old wrote in an Instagram comment Sunday.

The couple has been married since August 2010, and Kimberly shared a touching message for James earlier this year, wishing for “many many many many more birthdays” together.

“May this year bring you so much laughter, dancing, deepening connection with God, exceptional health and exquisite beauty all around,” she wrote via Instagram in March, calling her husband a “treasure.”

Kimberly and the little ones supported James later that same month when he competed as a griffin on the “Masked Singer.”

Before being unmasked, the “Pose” alum praised his family for helping him navigate a “really tough year.”

He told viewers, “I would not have gotten through this without them. They make me smile on all the tough days, and they’re strong for me when I sometimes can’t be. They stood beside me through it all. They’re my safe space, my home.”

James was diagnosed with cancer in August 2023.

By the time he shared the news the following year, he felt “cautiously optimistic” and told People, “I’m in a place of healing, my energy levels are great.

“When I’ve been out of the woods completely for what feels like a responsible amount of time, I’ll circle back and let you know,” he clarified in November 2024.