He's making jokes, but a ruptured appendix is very serious, due to the threat of infection. Here's hoping Stephen recovers quickly and completely! Via HuffPost:

First this fall, another round with COVID-19 shuttered Stephen Colbert’s “The Late Show.” Now the show is again sidelined as the host recovers from a burst appendix.

The comedian revealed on social media Monday that he’s recovering after surgery, wiping out planned shows for Tuesday, Wednesday and Thursday.

“Going forward, all emails to my appendix will be handled by my pancreas,” he joked.