Hours after he announced he wouldn't be able to make the "Dawson's Creek" reunion on Sept. 10, James Van Der Beek who was diagnosed with stage 3 colorectal cancer in August 2023 made a surprise appearance.The 48-year-old actor, who was set to read the pilot along with the original cast for a charity event on Monday, appeared virtually to thank his fellow castmates and fans."I have been looking forward to this night for months and months ever since my angel Michelle Williams said she was putting it together," Van Der Beek said in a video played for the audience, which fans later posted on social media. "I can't believe I'm not there. I can't believe I don't get to see my castmates, my beautiful cast, in person."ACTOR WITH COLORECTAL CANCER SHARES SIMPLE SIGN THAT HE IGNORED: I HAD NO IDEA"And just I wanted to stand on that stage and thank every single person in the theater for being here tonight," he continued. "From the cast to the crew to everybody who's doing anything and has been so generous, and especially every single last one of you you are the best fans in the world.""Thank you for coming. It's just absolutely humbling just how much you did for this night, and I just want to say thank you. Thank you to every single person here," he added. "And, obviously, on 'Dawson's Creek,' I had no understudy, but this is Broadway, and I needed one. So we figured we'd try to find somebody who had never understudied in this theater before."He then introduced Lin-Manuel Miranda as his replacement for the event.Hours prior, Van Der Beek said he was "gutted" to not attend the event after contracting two stomach viruses."This is the evening Id been looking forward to MOST since my angel Michelle Williams said she was putting it together, way back in January," he wrote on Instagram."So you can imagine how gutted I was when two stomach viruses conspired to knock me out of commission and keep me grounded at the worst possible moment," he explained. "Despite every effort I wont get to be there. I wont 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."In his post, Van Der Beek revealed he would be replaced by Miranda for the reunion.He called Miranda "a ridiculously overqualified replacement who would have been #1 on my wishlist (had I ever dreamed hed be available)."A representative for Van Der Beek did not immediately respond to Fox News Digital's request for comment.Van Der Beek revealed last November that he was undergoing treatment for colorectal cancer, and earlier this year, he talked about the "hardest year" of his life."When I was younger, I used to define myself as an actor, which was never all that fulfilling, and then I became a husband it was much better, and then I became a father that was the ultimate," he said to his 1.6 million followers on Instagram on March 8.JAMES VAN DER BEEK MISTOOK CANCER SYMPTOMS FOR PROBLEMS WITH HIS DIETThe father-of-six pointed out that during his cancer battle he was forced to "look my own mortality in the eye.""I had to come nose to nose with death," he remarked. "And all those definitions that I cared so deeply about were stripped from me.""I was away for treatment, so I could no longer be a husband who was helpful to my wife," Van Der Beek continued. "I could no longer be a father who could pick up his kids and put them to bed and be there for them. I could not be a provider because I wasnt working."LIKE WHAT YOURE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWSDuring hiscancer journey, the actor admitted he began to question if he was "just a too-skinny, weak guy, alone in an apartment with cancer what am I?""I am worthy of Gods love simply because I exist," Van Der Beek shared. "And if Im worthy of Gods love, shouldnt I also be worthy of my own?""As I move through this healing portal toward recovery," Van Der Beek said, "I wanted to share that with you because that revelation that came to me was in no small part to all the prayers and the love that had been directed toward me."He went on to say, "I certainly dont claim to know what God is or explain God, my efforts to connect to God are an ongoing process that is a constant unfolding mystery to me."But, if its a trigger that feels too religious, you can take the word God out in your mind and it can simply be I am worthy of love. Because you are."