"Don't Know Why" is a song written by Jesse Harris which originally appeared on his 1999 album, "Jesse Harris & the Ferdinandos".
 It was the second single by American singer Norah Jones from her debut studio album "Come Away with Me" (2002).
 Jones's version peaked at No. 30 on the U.S. "Billboard" Hot 100 and was a critical success, helping establish her as a respected new artist, and subsequently her album sold extremely well.
 The single went on to win three Grammy Awards in 2003 for Record of the Year, Song of the Year, and Best Female Pop Vocal Performance.
 It remains Jones's biggest hit single in the United States to date, and her only one to reach the top 40 of the "Billboard" Hot 100.
 The single was also a hit internationally and reached top 10 in several countries.
 The song charted at 459 in "Blender" magazine's 500 Greatest Songs Since You Were Born.
Hanson is an American pop rock band from Tulsa, Oklahoma, United States, formed by brothers Isaac (guitar, bass, piano, vocals), Taylor (keyboards, piano, guitar, drums, vocals) and Zac (drums, piano, guitar, vocals).
 Supporting members include Dimitrius Collins (keyboards, guitar), and Andrew Perusi (bass) who have toured and performed live with the band since 2007.
 They are best known for the 1997 hit song "MMMBop" from their debut album released through Mercury, Polygram, "Middle of Nowhere", which earned three Grammy nominations.
 Despite the enormous commercial success of "Middle of Nowhere", the band suffered from the merger that eliminated their label, Mercury Records .
 The group was moved to Island Def Jam Music Group, which they eventually left after a conflict with the label.
 Hanson has sold over 16 million records worldwide and have had 8 top 40 albums and 6 top 40 singles in the US, as well as 8 top 40 singles in the UK.
 The band now records under its own independent record label, 3CG Records.
Jeffrey Travis Andrew "Jeff" Phillips (born November 1948) is an Australian TV show host, personality, musical theatre actor and pop singer active from 1966 to the early 1990s.
 As a pop singer, he had a Top 40 hit on the "Go-Set" singles chart with a cover version of The Shirelles' 1961 hit, "Baby It's You".
 At the Logie Awards of 1970, he won the Best New Talent category for hosting his own ABC-TV pop show, "Sounds Like Us".
 In the early 1970s he hosted a series of teen pop music shows, "Happening '71" and "Happening '72".
 In July 1972 Phillips won a song prize at the Fifth Olympiad of Song, held in Athens, performing his self-written work, "Gloria"; the prize money was 100,000 drachmae (AUD $2,797).
 Although he issued further singles, until the early 1980s, he had no other national Top 40 chart success.
 From July 1985 to October 1987 he appeared in the Australian stage production of "Cats" in the role of Rum Tum Tugger in both the Sydney run and the Melbourne season; he also performed on the original Australian cast album.
Charles Eugene "Pat" Boone (born June 1, 1934) is an American singer, composer, actor, writer, television personality, motivational speaker, and spokesman.
 He was a successful pop singer in the United States during the 1950s and early 1960s.
 He sold more than 45 million records, had 38 top-40 hits, and appeared in more than 12 Hollywood films.
"Mexico" is the title of a 1961 instrumental recording by American bassist, orchestra leader, and Rockabilly Hall of Fame member Bob Moore.
 The song was written by Boudleaux Bryant.
 Moore was a noted session musician in the 1950s and 1960s who worked with Elvis Presley, Pat Boone, Roy Orbison, and Brenda Lee, among others.
 The song "Mexico" is credited to Bob Moore and His Orchestra, and in the fall of 1961 it became the only single where Moore is listed as an artist to reach the Top 40 of the U.S. "Billboard" Hot 100 chart.
 The song peaked at #7 and spent ten weeks in the Top 40.
 Moreover, it reached #1 on the Easy Listening chart, remaining at the top for one week in October 1961.
 It reached #22 on the R&B chart.
 Outside the U.S., "Mexico" was a #1 hit in both Australia and Germany, and it sold over two million records worldwide.
The following is a comprehensive discography of Poison, an American rock band that achieved huge success in the mid- 1980s to mid- 1990s.
 To date, the band has sold over 45 million records worldwide and has sold more than 15 million records in the United States alone.
 The band has also charted ten singles to the Top 40 of the "Billboard" Hot 100, including six Top 10 singles and the Hot 100 number-one single, "Every Rose Has Its Thorn".
Poison is an American rock band that achieved great commercial success in the mid-1980s to the mid-1990s.
 Poison has sold over 40 million records worldwide and has sold 15 million records in the United States alone.
 The band has also charted ten singles to the Top 40 of the "Billboard" Hot 100, including six Top 10 singles and the Hot 100 number-one, "Every Rose Has Its Thorn".
 The band's breakthrough debut album, the multi-platinum "Look What the Cat Dragged In", was released in 1986 and they hit their peak with the second album, "Open Up and Say... Ahh!
", which became the band's most successful album, being certified 5x platinum in the US.
 The popularity continued into the new decade with their third consecutive multi-platinum selling album, "Flesh & Blood".
"A Song of Joy" ("Himno de la alegría") is the title of a popular rock song by the Spanish singer and actor Miguel Ríos.
 The song is set to the tune the Ninth Symphony by Ludwig van Beethoven, as arranged by Waldo de los Rios, who specialized in arranging classical music to contemporary rhythms.
 The single was enormously popular in many countries in 1970 (see 1970 in music), reaching number one on music charts in Australia, Canada, Germany, Switzerland, and the Easy Listening chart in the United States.
 On the U.S. pop chart, the song peaked at number 14 and was the only Top 40 hit for Ríos.
 In the United Kingdom, the song reached number 16 on the British pop chart.
 In Germany, the song is the most successful pop hymn ever.
Sir Elton Hercules John, (born Reginald Kenneth Dwight; 25 March 1947), is an English singer, pianist, and composer.
 He has worked with lyricist Bernie Taupin as his songwriting partner since 1967; they have collaborated on more than 30 albums to date.
 In his five-decade career Elton John has sold more than 300million records, making him one of the best-selling music artists in the world.
 He has more than fifty Top 40 hits, including seven consecutive No. 1 US albums, 58 "Billboard" Top 40 singles, 27 Top 10, four No. 2 and nine No. 1.
 For 31 consecutive years (1970–2000) he had at least one song in the "Billboard" Hot 100.
 His tribute single, re-penned in dedication to the late Princess Diana, "Candle in the Wind 1997" sold over 33million copies worldwide and is the best-selling single in the history of the UK and US singles charts.
 He has also composed music, produced records, and has occasionally acted in films.
 John owned Watford Football Club from 1976 to 1987, and 1997 to 2002.
 He is an honorary Life President of the club, and in 2014 had a stand named after him at the club's home stadium.
Used Heart for Sale is the debut studio album of American country music singer Gary Allan.
 It was released on September 24, 1996 on the Decca Records Nashville label.
 This was Allan's first studio album, and has been certified gold by the RIAA.
 It produced four singles on the "Billboard" Hot Country Songs charts: "Her Man", "Living in a House Full of Love", "From Where I'm Sitting", and "Forever and a Day".
 While "Her Man" reached Top 10 on the country charts, none of the other three singles reached Top 40.

Question: This successful pop singer who sold more than 45 million records collaborated with the musician of what song that reached Top 40 in 1961?
Answer: Mexico