Question: Catherine Louise Sagal (born January 19, 1954) is an American actress and singer-songwriter, she's know as well for starring in the role of Cate Hennessy, on the show "8 Simple Rules", is an American sitcom, originally starring who as the father?

Context paragraphs:
List of 8 Simple Rules episodes: "8 Simple Rules for Dating My Teenage Daughter" is an American television sitcom that originally aired on ABC from September 17, 2002 to April 15, 2005.  Loosely based on humor columnist W. Bruce Cameron's book of the same name, the show starred John Ritter during its first season.  After Ritter's sudden death, Katey Sagal took over the show's starring position for the rest of the series' run.  Overall, 76 episodes were made over three seasons.

Kaley Cuoco: Kaley Christine Cuoco ( ; born November 30, 1985) is an American actress.  After a series of supporting film and television roles in the late 1990s, she landed her breakthrough role as Bridget Hennessy on the ABC sitcom "8 Simple Rules", on which she starred from 2002 to 2005.  Thereafter, Cuoco appeared as Billie Jenkins on the final season of the television series "Charmed" (2005–2006).  Since 2007, she has starred as Penny on the CBS sitcom "The Big Bang Theory", for which she has received Satellite, Critics' Choice, and People's Choice Awards.  Cuoco's film work includes roles in "To Be Fat like Me" (2007), "Hop" (2011) and "Authors Anonymous" (2014).  She received a star on the Hollywood Walk of Fame in 2014.

Martin Spanjers: Martin Brian Spanjers (born February 2, 1987) is an American actor.  He played Rory Hennessy on the ABC sitcom "8 Simple Rules" from 2002 to 2005, for which he won a Young Artist Award in 2004.

Billy Aaron Brown: Billy Aaron Brown (born July 28, 1981), is an American actor.  He is best known for playing the character Kyle on the sitcom "8 Simple Rules".

Suzy Nakamura: Suzy Nakamura is an American actress.  Nakamura is known for her many guest appearances on sitcoms such as "According to Jim", "Half and Half", "8 Simple Rules", "Curb Your Enthusiasm" and "How I Met Your Mother" and her recurring role in the early seasons of the drama "The West Wing" as assistant to the Sam Seaborn character, as well as Dr. Miura in the ABC sitcom "Modern Family".

Nikki Danielle Moore: Nikki Danielle Moore is an American actress best known as the character "Jenna Sharpe" on the sitcom "8 Simple Rules" from 2003 to 2005.

Katey Sagal: Catherine Louise Sagal (born January 19, 1954) is an American actress and singer-songwriter.  She is best known for her role as Peggy Bundy, Al's sarcastic, lazy, bon bon-eating wife, on "Married... with Children" and for her role voicing the character Leela on the animated science-fiction series "Futurama" from 1999 to 2003 and 2008 to 2013, as well as for starring on the show "8 Simple Rules" in the role of Cate Hennessy.  In the latter role, she worked with John Ritter until his death, leading to Sagal's taking over as the series lead for the remainder of the show's run.  Sagal has been married to "Sons of Anarchy" creator Kurt Sutter since 2004.  Currently, Sagal is a series regular on CBS's Superior Donuts.

8 Simple Rules: 8 Simple Rules (originally 8 Simple Rules for Dating My Teenage Daughter for the first season) is an American sitcom, originally starring John Ritter and Katey Sagal as middle-class parents Paul and Cate Hennessy raising a family of three.  Kaley Cuoco, Amy Davidson and Martin Spanjers co-starred as their teenage kids; Bridget, Kerry and Rory Hennessy.  The series ran on ABC from September 17, 2002 to April 15, 2005.  The first season focused on Paul being left in charge of the kids after Cate takes a full-time job as a nurse, with comedic emphasis on his often strict rules concerning his daughters and dating.  The series' name and premise were derived from the book "8 Simple Rules for Dating My Teenage Daughter: And Other Tips from a Beleaguered Father (Not That Any of Them Work)" by W. Bruce Cameron.

Amy Davidson: Amy Davidson (born September 15, 1979) is an American actress.  She is known for playing Kerry Hennessy in the ABC sitcom "8 Simple Rules".

Kala Savage: Kala Lynne Savage (born October 16, 1978) is an American actress.  She is best known for the TV series "Undressed", "Santa Barbara", and "8 Simple Rules".

Supporting paragraphs: Katey Sagal 8 Simple Rules
Answer: John Ritter