John Ritter died on September 11, 2003, and Hollywood has never quite gotten over it.
He was 54, seemingly healthy, and in the middle of taping a hit sitcom.
The suddenness is what people still talk about.
On that Thursday afternoon, Ritter was working on "8 Simple Rules for Dating My Teenage Daughter" when he fell ill on set.
He was rushed to a Burbank hospital, where doctors discovered an aortic dissection.
What makes the story linger is what co-stars have said since.
Kaley Cuoco, who played his daughter on the show, has described him as the warmest person she ever worked with.
Katey Sagal, his on-screen wife, has spoken about the shock of losing him mid-season.
The network shut down production, then returned weeks later with a shortened season that addressed his character's death directly.
It remains one of the most-watched episodes in the show's run.
Ritter's career had already spanned three decades before that fall.
He was Jack Tripper on "Three's Company," a role that won him an Emmy and made him a household name in the late '70s and early '80s.
But younger audiences knew him as Paul Hennessy, the exasperated dad trying to raise three kids.
The role gave him a second act, and he was only getting started when it ended.
His family has kept his memory alive in public ways.
His widow, Amy Yasbeck, founded the John Ritter Foundation for Aortic Health, which pushes for awareness and early detection.
His son, Jason Ritter, has built his own acting career and often speaks about his father in interviews.
The 2003 Emmy Awards included a tribute to Ritter, and his "8 Simple Rules" castmates attended together.
Sagal has said the grief was unlike anything she had experienced on a set.
Two decades later, fans still post clips of Jack Tripper and Paul Hennessy.
So does the sadness that followed. **Our take:** Ritter is one of those rare stars whose death felt personal to people who never met him, because his characters lived in their living rooms.
His legacy isn't just the sitcoms, though.
It's the foundation his family built out of a tragedy that could have stayed private.
Final Thoughts
That's a harder thing to pull off than any punchline.