Question: Which season of American Idol featured the artist who sings with John Mayer on Who You Love as a guest judge?

full_context: Document 1: 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 2: Part of Me (Katy Perry song): "Part of Me" is a song by American singer Katy Perry, released as the lead single from "". It was written by Perry, and Bonnie McKee, with production and additional writing by Dr. Luke, Max Martin, and Cirkut. The song was not included on the original edition of "Teenage Dream" because Perry felt that it did not fit the composition of the album. A demo of the song leaked online in late 2010, amid speculation that the lyrics were directed to the singer's ex-boyfriend Travie McCoy. "Part of Me" was re-worked and officially released on February 13, 2012, through Capitol Records with artwork by art director Gavin Taylor and photography by Mary Ellen Matthews.
Document 3: Who Says (John Mayer song): "Who Says" is the thirteenth single released by American singer-songwriter John Mayer, and the first to be released from his fourth studio album, "Battle Studies". It is Mayer's first studio recorded single release since "Say" in 2007. On September 25, 2009, "Who Says" was released on John Mayer's official website.
Document 4: The One That Got Away (Katy Perry song): Originally titled ``In Another Life '', the song was produced by Dr. Luke and Max Martin, both of whom co-wrote it with Perry. It is a midtempo pop song positioned on the piece of E major and has a tempo of 134 beats per minute. Joanna Holcombe from Yahoo! Music noted that the song is about first loves. Leah Greenblatt from Entertainment Weekly, said that the song is`` a midtempo ode to a summer - after - high - school love with whom she recalls sharing Mustang makeout sessions to Radiohead '''. Michael Wood from Spin magazine said that the song is one of the album's quieter cuts and that it recall (s) ``Perry's singer - songwriter days at L.A.'s Hotel Café ''. The song follows the chord progression of E -- G ♯ m -- C ♯ m -- A, and Perry's vocal range spans from B to E. Kitty Empire noticed that Perry's vocal is wistful throughout the song and that the references to June and Johnny Cash were unexpected. Rob Sheffield from Rolling Stone stated that when Perry sings,' I was June, and you were my Johnny Cash, '`` it's understood that she's thinking of the scrubbed - up Hollywood version of June and Johnny, from Walk the Line.'' In 2017, the singer revealed that ``The One That Got Away ''was about Josh Groban.
Document 5: 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 6: 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 7: 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 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: Why I Love You (Jay-Z and Kanye West song): "Why I Love You" is a song by American hip hop artists Kanye West and Jay-Z, from their first collaborative album "Watch the Throne" (2011). The song features pop musician Mr. Hudson who is signed to West's GOOD Music label. "Why I Love You" heavily samples French house duo Cassius' 2010 single "I <3 U So", which itself is based upon a sample from the original 1971 version of "I Feel a Song (In My Heart)" by Sandra Richardson. The song almost entirely features Jay-Z rapping and only contains a few lines provided by West. Lyrically, the song is about the people who have stood in the way of Jay-Z throughout the year and expresses themes of victory and anger. The song received generally positive reviews from music critics, who normally praised the production.
Document 10: 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 11: Your Love Is a Song: "Your Love Is a Song" was written and recorded by the alternative rock band Switchfoot. It was first released as a single to the iTunes Store in Australia, and became the third radio single from the band's seventh studio album, "Hello Hurricane".
Document 12: 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 13: Somebody to Love (Jefferson Airplane song): Written by The Great Society guitarist Darby Slick after realizing his girlfriend had left him, and first performed by that band, which included his then - sister - in - law Grace Slick on vocals, the song made little impact outside of the club circuit in the Bay Area. The song was released in 1966 as a single with the B - side another Darby Slick composition titled ``Free Advice ''on the North Beach subsidiary of Autumn Records, and received minimal circulation outside of San Francisco. San Francisco in the mid - '60s was the epicenter of free love, but Darby Slick saw a downside to this ethos, as it could lead to jealousy and disconnect. This song champions loyalty and monogamy, as the singer implores us to find that one true love that will nurture us and get us through the tough times.
Document 14: Who You Love: ``Who You Love ''is a song written and performed by John Mayer and Katy Perry for Mayer's sixth studio album, Paradise Valley (2013). It appears as the sixth song on the album and is the third single from the record. Mayer co-produced the song with Don Was and released it as an Internet download on August 12, 2013. Lyrically,`` Who You Love'' is a ballad about accepting falling in love with someone, on the theory that ``you love who you love ''. The song has been praised by critics and has received mostly positive reviews.
Document 15: The One That Got Away (Katy Perry song): "The One That Got Away" is a song by American singer Katy Perry for her third studio album, "Teenage Dream" (2010). The song was produced by Dr. Luke and Max Martin, both of whom also co-wrote the song with Perry. The song is a mid-tempo pop ballad about a lost love. It features references to the rock band Radiohead as well as the relationship of Johnny Cash and June Carter Cash to express the strength of the relationship. The song was released in October 2011 by Capitol Records as the album's sixth single.
ground_truth: season nine
sub_queries: who sings with john mayer on who you love Answer: Katy Perry
Which season of American Idol featured Katy Perry as a guest judge? Answer: season nine