Henry Winkler Recalls Comedian John Ritter's Unique Talent, 15 Years After His Death

John Ritter graced the Hollywood screen with his lighthearted humor and unique acting talent from the '70s to the late '90s. After gaining fame on Three's Company, the actor went on to star in Hooperman, Problem Child, 8 Simple Rules and Bad Santa, among many others.

While his cheery personality is what made him so lovable, Ritter was hiding a horrific health issue behind his contagious smile.

PHOTOS: Carrie Fisher’s Daughter Billie Lourd Breaks Down At Private Memorial

In 2003, an aortic dissection caused his sudden death at age 54.

Now, 15 years later, REELZ's docuseries, John Ritter: Behind Closed Doors, looks back at the actor's fabulous life and career, and invites people from his past to comment on his accomplishments, persona and abrupt passing.

"There are very few actors who could swim from one genre to another without breaking the water," says actor and former pal, Henry Winkler, in the show teaser.

PHOTOS: Heartbreaking Goodbye: Inside Carrie & Debbie’s Double Memorial

"People admired him but did not understand the depths of his ability," he adds.

John Ritter: Behind Closed Doors airs Saturday, September 8 at 9:00 ET / 8:00 PT on REELZ.