Nearly 18 years after his sudden death, Kaley Cuoco is still missing her on-screen dad John Ritter.

On Wednesday, ABC will honor the late Three’s Company actor with the special TV event Superstar: John Ritter. Ahead of the special airing, Kaley shared the trailer on Instagram where she can be heard saying that “John was like no one [she has] have ever met.” The clip also featured fellow Three’s Company actress Suzanne Somers, late-night talk show host Jimmy Kimmel, actor Bryan Cranston and others who look back at John’s legendary career through personal anecdotes.

“SuperStar Don’t miss this next week.. all about my friend John Ritter ❤️,” Kaley captioned the video.

instagramView full post on Instagram

After watching the upcoming special’s trailer, fans left heartfelt comments. “Legend ❤️🙏,” one person wrote. “Beautiful tribute ❤️,” another added. “He was incredible and he’s missed every day. ❤️,” a different fan said.

Before Kaley rose to fame on The Big Bang Theory as Penny, she got her start in Hollywood alongside John on the ABC sitcom 8 Simple Rules for Dating My Teenage Daughter. Kaley and John famously starred in the TV series together as father-daughter duo Bridget and Paul Hennessy.

Unfortunately, while filming the show’s second season, John fell ill on set and was rushed to the emergency room. It was initially thought that he had suffered a heart attack, but doctors later discovered it was an aortic dissection, which is “a break in the main artery that carries blood from the heart.” This information wasn’t found out in time and John died that same day on September 11, 2003.

Over the years, Kaley has remembered John on the the anniversary of his death, and she's also shared significant memories of the actor. In an interview for Variety’s Actors on Actor series, The Flight Attendant actress opened up to WandaVision star Elizabeth Olsen about a talk the two had that she still thinks about today.

"I remember conversations when I was 15 years old where [John] said, 'You have to remember when you're on a set, it's like a tree. Number one's here, and any way you act is all trickling down that tree,’” she said. “You can be a boss, you can be a great actor, you can get work done, but you can just be nice.”

Superstar: John Ritter airs on Wednesday, August 25, 2021 at 10 p.m. ET on ABC.