DEBUTED in 2002, “American Idol” had originally planned on having four judges following the “Pop Idol” format. However, only three judges had been found by the time of the audition round in the first season, namely Randy Jackson, Paula Abdul and Simon Cowell.

    In the second season, New York radio personality Angie Martinez had been hired as a fourth judge but withdrew after only a few days of auditions due to not being comfortable with giving deep criticism. The show decided to continue with the three judges format until season eight. All three original judges stayed on the judging panel for eight seasons.

    In season eight, Latin Grammy Award-nominated singe and record producer Kara DioGuardi was added as a fourth judge. Abdul left the show before season nine after failing to agree to terms with the show producers. Emmy Award-winning talk show host Ellen DeGeneres replaced Abdul for that season, but left after just one season. On Jan. 11, 2010, Cowell announced he was leaving the show to pursue introducing his show “The X Factor” to the United States for 2011. DioGuardi also left the show Sept. 3 after two seasons.

    Guest judges may occasionally be introduced. For example, Donna Summer, Quentin Tarantino and some of the mentors joined as judges to critique the performances in season three final rounds. Guest judges were used in the audition rounds for seasons four and nine. Season four guest judges included Gene Simmons, Brandy Norwood, Mark McGrath and Kenny Loggins. Season nine guest judges included Victoria Beckham, Mary J. Blige, Kristin Chenoweth, Neil Patrick Harris, Joe Jonas, Avril Lavigne, Katy Perry and Shania Twain.

    The first season was presented by Ryan Seacrest and Brian Dunkleman. Dunkleman quit after the first season but would have been fired had he not left, and Ryan Seacrest has presented the show alone since.(SD-Agencies)