The "dog" has officially left the house.

Randy Jackson, the only original American Idol judge who still plays a role on the Fox reality singing competition, has officially announced he's leaving.

Jackson served as Idol's in-house mentor for Season 13, replacing Jimmy Iovine. Prior to last season, he had always served as a regular judge on the panel.

"After 13 seasons, I felt now was the perfect time to leave American Idol," Jackson said in a statement obtained by People. "I'm proud to have been a part of a series that discovered some incredible artists and will go down in history as one of the most successful television shows ever. A true original, Idol started it all. Onto what's next."

After the show's twelfth season aired, Jackson had made a similar announcement in May 2013 he was leaving American Idol. However, he returned as a mentor for all of Idol's contestants, who were judged by Jennifer Lopez, Keith Urban and Harry Connick Jr.

"Randy has been such an integral part of American Idol since day one, both as a judge and as a mentor. He's provided great advice and support, shaping the success of so many Idols we have discovered over the years," Fox also said in a statement, according to People. "We wish him all the best in his next chapter. Randy will always be part of our Idol family and we hope he'll visit from time to time."

With Jackson's departure, host Ryan Seacrest remains the only mainstay over the course of the show's 14 seasons. American Idol's fourteenth edition is set to premiere in January on Fox.

Lopez, Urban and Connick Jr. will all be returning as judges next season.
About The Author: Elizabeth Kwiatkowski
Elizabeth Kwiatkowski is Associate Editor of Reality TV World and has been covering the reality TV genre for more than a decade.