Question: In what season was the performer of Encore a guest judge on American Idol?

full_context: Document 1: American Idol: The fourteenth season premiered on January 7, 2015. Ryan Seacrest returned to host, while Jennifer Lopez, Keith Urban and Harry Connick, Jr. returned for their respective fourth, third and second seasons as judges. Eighth season runner-up Adam Lambert filled in for Urban during the New York City auditions. Randy Jackson did not return as the in-house mentor for this season.
Document 2: Just Go (Lionel Richie song): "Just Go" is a single by Lionel Richie from his 2009 album "Just Go". The song, a duet with Akon, was released on March 12, 2009 and - following its UK release - was described by noted R&B writer Pete Lewis of the award-winning 'Blues & Soul' as "a seductively tuneful single with a Caribbean-tinged lilt".
Document 3: Away (Enrique Iglesias song): "Away" is the first single released from Spanish singer-songwriter Enrique Iglesias' "Greatest Hits" album. The song features vocals from American pop-rap singer-songwriter Sean Garrett. The single was released on 11 November 2008. "Away" was originally intended to be on Sean Garrett's debut solo album "Turbo 919", but the decision was made to include it on Iglesias' album instead. The song debuted on the UK Singles Chart, at #132 on the week of the physical single release.
Document 4: American Idol: The show 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. A fourth judge, radio DJ Stryker, was originally chosen but he dropped out citing "image concerns". In the second season, New York radio personality Angie Martinez had been hired as a fourth judge but withdrew only after a few days of auditions due to not being comfortable with giving out 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.
Document 5: Nothing Compares 2 U: Prince performed the song as a live duet with Rosie Gaines, subsequently released on his 1993 compilations The Hits / The B - Sides and The Hits 1, and the 2006 Ultimate Prince compilation. Prince also recorded a solo version of the song for his concert film, Rave Un2 the Year 2000, as well as for his 2002 live album, One Nite Alone... Live!
Document 6: Stuck on You (Lionel Richie song): "Stuck on You" is a song written by and originally recorded by Lionel Richie. It was the fourth single released from his second studio album "Can't Slow Down" released on May 1, 1984, by Motown, and achieved chart success, particularly in the U.S. and the UK, where it peaked at number three and number 12, respectively. The song differs from Richie's other compositions, as it displays a country pop influence rather than R&B. As such, the single's cover photo shows Richie wearing a cowboy hat, and indeed, "Stuck on You" peaked at number 24 on the country chart. "Stuck on You" reached number one on the Adult Contemporary chart, Richie's seventh chart topper. The song marks Lionel Richie's country music debut.
Document 7: American Idol: Guest judges may occasionally be introduced. In season two, guest judges such as Lionel Richie and Robin Gibb were used, and in season three Donna Summer, Quentin Tarantino and some of the mentors also joined as judges to critique the performances in the final rounds. Guest judges were used in the audition rounds for seasons four, six, nine, and fourteen such as Gene Simmons and LL Cool J in season four, Jewel and Olivia Newton-John in season six, Shania Twain in season eight, Neil Patrick Harris, Avril Lavigne and Katy Perry in season nine, and season eight runner-up, Adam Lambert, in season fourteen.
Document 8: American Idol: In season eight, Latin Grammy Award-nominated singer–songwriter and record producer Kara DioGuardi was added as a fourth judge. She stayed for two seasons and left the show before season ten. Paula Abdul left the show before season nine after failing to agree terms with the show producers. Emmy Award-winning talk show host Ellen DeGeneres replaced Paula Abdul for that season, but left after just one season. On January 11, 2010, Simon Cowell announced that he was leaving the show to pursue introducing the American version of his show The X Factor to the USA for 2011. Jennifer Lopez and Steven Tyler joined the judging panel in season ten, but both left after two seasons. They were replaced by three new judges, Mariah Carey, Nicki Minaj and Keith Urban, who joined Randy Jackson in season 12. However both Carey and Minaj left after one season, and Randy Jackson also announced that he would depart the show after twelve seasons as a judge but would return as a mentor. Urban is the only judge from season 12 to return in season 13. He was joined by previous judge Jennifer Lopez and former mentor Harry Connick, Jr.. Lopez, Urban and Connick, Jr. all returned as judges for the show's fourteenth and fifteenth seasons.
Document 9: Queen (band): In 1999, a Greatest Hits III album was released. This featured, among others, "Queen + Wyclef Jean" on a rap version of "Another One Bites the Dust". A live version of "Somebody to Love" by George Michael and a live version of "The Show Must Go On" with Elton John were also featured in the album. By this point, Queen's vast amount of record sales made them the second best selling artist in the UK of all time, behind the Beatles. In 2002, Queen were awarded the 2,207th star on the Hollywood Walk of Fame, which is located at 6358 Hollywood Blvd. On 29 November 2003, May and Taylor performed at the 46664 Concert hosted by Nelson Mandela at Green Point Stadium, Cape Town, to raise awareness of the spread of HIV/AIDS in South Africa. May and Taylor spent time at Mandela's home, discussing how Africa's problems might be approached, and two years later the band was made ambassadors for the 46664 cause.
Document 10: Louder Than Words (album): Louder Than Words is the fourth studio album by Lionel Richie, released on April 16, 1996. It also marked the first time he released a studio album of new material in ten years. In 1992 he released just three new tracks on his compilation album "Back to Front". "Louder Than Words" debuted at #33 on the "Billboard" 200 with a disappointing sales of 28,000 copies, and only peaked at #28.
Document 11: American Idol: Beginning in the tenth season[citation needed], permanent mentors were brought in during the live shows to help guide the contestants with their song choice and performance. Jimmy Iovine was the mentor in the tenth through twelfth seasons, former judge Randy Jackson was the mentor for the thirteenth season and Scott Borchetta was the mentor for the fourteenth and fifteenth season. The mentors regularly bring in guest mentors to aid them, including Akon, Alicia Keys, Lady Gaga, and current judge Harry Connick, Jr..
Document 12: Encore (Lionel Richie album): Encore is the first live album by Lionel Richie, released on November 26, 2002. Various international versions also included "Goodbye", "To Love a Woman" (featuring Enrique Iglesias), "Don't Stop the Music" and "Tender Heart". The material on the album was recorded at Wembley Arena in London, England in May 2001.
Document 13: American Idol: American Idol employs a panel of judges who critique the contestants' performances. The original judges were record producer and music manager Randy Jackson, pop singer and choreographer Paula Abdul and music executive and manager Simon Cowell. The judging panel for the most recent season consisted of country singer Keith Urban, singer and actress Jennifer Lopez, and jazz singer Harry Connick, Jr. The show was originally hosted by radio personality Ryan Seacrest and comedian Brian Dunkleman, with Seacrest continuing on for the rest of the seasons.
Document 14: American Idol: With the exception of seasons one and two, the contestants in the semifinals onwards perform in front of a studio audience. They perform with a full band in the finals. From season four to season nine, the American Idol band was led by Rickey Minor; from season ten onwards, Ray Chew. Assistance may also be given by vocal coaches and song arrangers, such as Michael Orland and Debra Byrd to contestants behind the scene. Starting with season seven, contestants may perform with a musical instrument from the Hollywood rounds onwards. In the first nine seasons, performances were usually aired live on Tuesday nights, followed by the results shows on Wednesdays in the United States and Canada, but moved to Wednesdays and Thursdays in season ten.
Document 15: All Night Long (All Night): ``All Night Long (All Night) ''7'' cover Single by Lionel Richie from the album Ca n't Slow Down B - side`` Wandering Stranger ''Released August 31, 1983 Format 7 ``, 12'' Length 4: 20 (Single edit) 6: 19 (Album version) Label Motown Songwriter (s) Lionel Richie Producer (s) Lionel Richie James Anthony Carmichael Lionel Richie singles chronology`` My Love ''(1983) ``All Night Long (All Night)'' (1983)`` Running with the Night ''(1983) ``My Love'' (1983)`` All Night Long (All Night) ''(1983) ``Running with the Night'' (1983)
ground_truth: season two
sub_queries: Encore >> performer Answer: Lionel Richie
In what season was Lionel Richie a guest judge on American Idol? Answer: season two