“Come and knock on our door! We've been waiting for you…” Sadly, the door to the now-famous Three’s Company apartment was closed forever last Thursday when actor John Ritter, 54, passed away on the set of his current comedy series 8 Simple Rules…For Dating My Teenage Daughter.

Ritter’s death was attributed to “aortic dissection,” a heart condition that the Emmy-award winning actor had not been previously diagnosed. His death came as an astonishment to everyone, including Ritter’s home network ABC. The show 8 Simple Rules had recently won “Choice TV Breakout Show” at the Teen Choice awards and consistently ranked in the Nielsen Primetime Top 10.

The network issued a release about the loss of one of their top stars: “All of us at ABC, Touchstone Television, and The Walt Disney Company are shocked and heartbroken at the terrible news of John’s passing.”

ABC also reports on their website, ABC.com, that the last three episodes of the show that Ritter had completed will be aired sequentially. The show will then take a somber note, with the characters dealing with the loss and grief and then slowly beginning to add more and more comedy to the top show.

Ritter was never a stranger to success. Fans of the hit Three’s Company will be pleased to note that the former “Jack Tripper” was nominated for both Golden Globe and Emmy awards for the comedic series, eventually garnering a Golden Globe as well as an Emmy in 1984 for his work on the show.

The award winning actor didn’t stop there, though. He was recognized for his work on a made-for-television movie with another Golden Globe nomination, in 1987, as well as another Globe nomination in 1988 for his critically successful drama series Hooperman.

Not one to forget where he came from, Ritter took such roles as “Little Ben Healy,” the beleaguered father in Problem Child and Problem Child 2.

The talented actor also pursued various roles on made-for-television movies, as well as other television series. Ritter soon began to embrace his skill for dramatic acting. He took roles such as the one that got him nominated for a Screen Actors Guild award for “Outstanding Performance By A Cast.”

A pointedly over-looked facet of the television and cinema actor was his ability to play on the stage, performing with his characteristic charisma in front of live audiences. Ritter has toured in numerous play productions, ranging from Tennessee Williams’ The Glass Menagerie to Shakespeare’s The Tempest.

Ritter’s last tour was with the latest Neil Simon play The Dinner Party, which ran extended for nine months. Once again, Ritter garnered critical reviews of his performances.

The man who was known for his pratfalls and physical slapstick on Three’s Company also lent his voice to the currently popular children’s show Clifford the Big Red Dog, airing on PBS. Ritter has been nominated for Daytime Emmys each of the three years the show has been on the air, beginning in 2001.

Ritter seemed to love acting on dramatic and comedic television series and guest-starred in shows ranging from Hawaii 5-0, Rhoda, Starsky and Hutch, to recently popular shows like Buffy the Vampire Slayer and Felicity, and most recently on the NBC hit comedy Scrubs. Ritter began his role as journalist-father Paul Hennessy on 8 Simple Rules… in 2002 to critical and Neilsen rating success.

One to continue working even as he began a new comedy series, Ritter starred in the 2002 romantic comedy Tadpole alongside Sigourney Weaver, and recently completed work on a Christmas-themed comedy. Bad Santa also stars Billy Bob Thornton and comedian Bernie Mac, along with Lauren Graham.

Private funeral services were held in Los Angeles on Monday, and ABC showed a memorial tribute to John Ritter in the usual 8 Simple Rules timeslot featuring clips from past shows and comments from co-stars past and present.

8 Simple Rules For Dating My Teenage Daughter is scheduled to begin its second season on Sept. 23, and by all accounts, John Ritter will be sorely missed.