"That Green Gentleman (Things Have Changed)" (often shortened to "That Green Gentleman") is a single by American rock band Panic at the Disco, from their second studio album "Pretty.
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" The song was the second song written by the band after they decided to scrap an album's worth of material, but was not played with "When the Day Met the Night" and "Nine in the Afternoon" at the various festivals Panic performed at during the summer of 2007.
"Closer" is a song by American recording artist Ne-Yo.
 The song was written and produced by Ne-Yo and Stargate.
 It was released as the lead single from Ne-Yo's third studio album "Year of the Gentleman" (2008).
"Gangnam Style" (Korean: 강남스타일 , ] ) is the 18th K-pop single by the South Korean musician Psy.
 The song was released on July 15, 2012, as the lead single of his sixth studio album "Psy 6 (Six Rules), Part 1", and debuted at number one on South Korea's Gaon Chart.
 On December 21, 2012, "Gangnam Style" became the first YouTube video to reach one billion and two billion views.
 The song's music video has been viewed over 2.9 billion times on YouTube, and was the most viewed video on YouTube from November 24, 2012, when it surpassed the music video for "Baby" by Justin Bieber featuring Ludacris, to July 10, 2017, when it was surpassed by the music video for "See You Again" by Wiz Khalifa featuring Charlie Puth.
"Perfect Gentleman" is the third single released from American recording artist Wyclef Jean's second studio album, "".
 It features a guest verse by rapper and co-writer Hope Harris.
 In the United States, the song reached number eight on Hot R&B/Hip-Hop Songs, and failed to chart on the "Billboard" Hot 100.
 Outside the United States, "Perfect Gentleman" peaked within the top ten of the charts in the United Kingdom, where the song was certified gold by the British Phonographic Industry.
"Stone Cold Gentleman" is a song performed by American contemporary R&B singer Ralph Tresvant, issued as the second single from his eponymous debut album.
 It originally appeared on the album under the title "Stone Cold Gentleman (Rizz's Interlude)", but the title was shortened for commercial release.
 The song features a rap from fellow New Edition member Bobby Brown; and it peaked at #34 on the "Billboard" Hot 100 in 1991.
"Gentleman" is a song recorded by English-Irish girl group The Saturdays from their fourth studio album "Living for the Weekend" (2013).
 It was released on 30 June 2013 as the third single from the album.
 It was written by Priscilla Renea, Lukas Nathanson and Scott Effman, with production by Ambience.
 The song hears the five-piece claim that finding a gentleman is difficult in modern society as compared to the 1990s.
"Gentleman" is a K-pop song by South Korean musician Psy released on April 12, 2013 (KST), serving as his 19th single.
 The song serves as the follow-up to his international hit single "Gangnam Style", which at the time of "Gentleman"'s release had been viewed on YouTube over 1 billion times.
 The first public performance of the song, with its associated dance, was unveiled at 6:30 pm on April 13 at Seoul World Cup Stadium in Seoul.
 A poster and Twitter message was released containing the main line of the song "I'm a mother f••••• gentleman"; The obscured word was later revealed to be "father".
"Let Nas Down" is a song by American hip hop recording artist J. Cole, taken from his second studio album "Born Sinner" (2013).
 The song was produced by Cole himself as a dedication to one of his idols, fellow American rapper Nas, with whom Cole was often compared to early in his career.
 He sampled the song "Gentleman" by Fela Kuti.
 The song peaked at #55 on the Hot R&B/Hip-Hop Songs.
Ne-Yo is African American and Chinese American.
 While a teenager, Ne-Yo wrote lyrics for other artists, such as Youngstown and Mario, for whom he wrote "Let Me Love You".
 The song became "one of the most-played songs on urban radio stations across the U.S." Ne-Yo has released four studio albums: "In My Own Words" (2006), "Because of You" (2007), "Year of the Gentleman" (2008), and "Libra Scale" (2010).
 His debut album, "In My Own Words", was released in early 2006 through Def Jam Recordings, and debuted at number one on "Billboard" 200.
 More than 301,000 copies were sold in the first week, and the album was certified Platinum by the Recording Industry Association of America after more than two million copies were sold in the United States and four million worldwide.
 His second album, "Because of You", was released on May 1, 2007, and its first single was "Because of You".
"Blow Ya Mind" is a song by American hip hop recording artist Styles P, featuring vocals and production from Swizz Beatz.
 The song, taken from his third studio album "Super Gangster (Extraordinary Gentleman)", was released October 9, 2007 as the album's lead single.
 "Blow Ya Mind" is considered to be the sequel to his 2002 debut single "Good Times" which was also produced by Swizz Beatz.

Question: What album was the song Gentleman on?
Answer: Psy 6 (Six Rules), Part 1