Not everyone knew what a hit James Corden's Carpool Karaoke would become.
The Late Late Show host recalls the initial process of booking the bit, when he couldn't even get "fifth rate" artists to sign on for an appearance.
"If you imagine an artist, just think of any artist in the world, they said no to it. I mean, everyone," Corden said in an interview on Howard Stern's SiriusXM radio show. "I'm talking, like, who's the dudes who did 'Cotton Eye Joe'? We were in those sorts of territories. ... And they're like, 'I'm not doing that.'"
Then came Mariah Carey, who ramped up the diva factor for the very first version of the segment. Corden explains that he first won over a woman from Carey's record label, who in-turn pitched the idea to Carey. The singer agreed to participate as promo for her Las Vegas residency.
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James Corden hilariously recalls Mariah Carey's refusal to sing on 'Carpool Karaoke'
NEW YORK, NY - FEBRUARY 12: Singer Mariah Carey and Nick Cannon attend MTV First: Mariah Carey's 'You're Mine (Eternal)' music video world premiere at MTV Studios on February 12, 2014 in New York City. (Photo by Larry Busacca/Getty Images)
LOS ANGELES, CA - JANUARY 18: Mariah Carey and Nick Cannon (R) arrive at the 20th Annual Screen Actors Guild Awards at the Shrine Auditorium on January 18, 2014 in Los Angeles, California. (Photo by Dan MacMedan/WireImage)
NEW YORK, NY - AUGUST 05: Nick Cannon (L) and Mariah Carey attend Lee Daniels' 'The Butler' New York premiere, hosted by TWC, DeLeon Tequila and Samsung Galaxy on August 5, 2013 in New York City. (Photo by Kevin Mazur/Getty Images for Samsung)
HOLLYWOOD, CA - NOVEMBER 17: TeenNick Chairman and HALO Awards host Nick Cannon and singer Mariah Carey attend Nickelodeon's 2012 TeenNick HALO Awards at Hollywood Palladium on November 17, 2012 in Hollywood, California. The show premieres on Monday, November 19th, 8:00p.m. (ET) on Nick at Nite. (Photo by Charley Gallay/Getty Images For Nickelodeon)
NEW YORK, NY - DECEMBER 15: Mariah Carey leaves the Beacon Theater on December 15, 2014 in New York City. (Photo by James Devaney/GC Images)
LOS ANGELES, CA - MARCH 14: Mariah Carey (L) and actor Jussie Smollett attend the Human Rights Campaign Los Angeles Gala 2015 at JW Marriott Los Angeles at L.A. LIVE on March 14, 2015 in Los Angeles, California. (Photo by Jason Kempin/Getty Images for Human Rights Campaign)
NEW YORK, NY - DECEMBER 03: Mariah Carey performs at the 82nd Annual Rockefeller Christmas Tree Lighting Ceremony at Rockefeller Center on December 3, 2014 in New York City. (Photo by James Devaney/WireImage)
NEW YORK, NY - DECEMBER 03: Singer Mariah Carey performs at the 82nd Annual Rockefeller Center Christmas Tree Lighting on December 3, 2014 in New York City. (Photo by Paul Zimmerman/WireImage)
SHANGHAI, CHINA - OCTOBER 19: (CHINA OUT) Singer Mariah Carey performs live during her 2014 China Tour on October 19, 2014 in Shanghai, China. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)
NEW YORK NY - AUGUST 26: Mariah Carey sighting on August 26, 2014 in New York City. (Photo by Josiah Kamau/BuzzFoto/FilmMagic)
HOLLYWOOD, CA - JULY 23: Singer Mariah Carey and actor Dwayne Johnson attend the after party for the premiere of Paramount Pictures' 'Hercules' at the Roosevelt Hotel on July 23, 2014 in Hollywood, California. (Photo by Alberto E. Rodriguez/WireImage)
CAP D'ANTIBES, FRANCE - JUNE 17: (EXCLUSIVE COVERAGE) Mariah Carey performs during Clear Channel Media And Entertainment And MediaLink Dinner at Hotel du Cap-Eden-Roc on June 17, 2014 in Cap d'Antibes, France. (Photo by Tony Barson/Getty Images for Clear Channel)
NEW YORK, NY - JUNE 09: Singer Mariah Carey announces the launch of her Go N'Syde bottle 'Butterfly' at the Saint Regis Hotel on June 9, 2014 in New York City. (Photo by Andrew H. Walker/Getty Images)
NEW YORK, NY - MAY 29: Singer Mariah Carey attends the 2014 Fresh Air Fund Honoring Our American Hero at Pier Sixty at Chelsea Piers on May 29, 2014 in New York City. (Photo by Monica Schipper/FilmMagic)
Mariah Carey performs during the World Music Awards at Monte Carlo Sporting Club, on May 27, 2014 in Monaco. AFP PHOTO / VALERY HACHE (Photo credit should read VALERY HACHE/AFP/Getty Images)
TODAY -- Pictured: Mariah Carey appears on NBC News' 'Today' show -- (Photo by: Peter Kramer/NBC/NBC NewsWire via Getty Images)
LOS ANGELES, CA - MAY 06: (EXCLUSIVE COVERAGE) Singer Mariah Carey attends Mishka B's Epic Bat Mitzvah at 1OAK on May 6, 2016 in Los Angeles, California. (Photo by Jeff Kravitz/FilmMagic)
LOS ANGELES, CA - MAY 06: (EXCLUSIVE COVERAGE) Stella Bulochnikov (L) and Mariah Carey attend Mishka B's Epic Bat Mitzvah at 1OAK on May 6, 2016 in Los Angeles, California. (Photo by Jeff Kravitz/FilmMagic)
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"She came out and said, 'Oh, I'm not singing today,' and she went, 'We'll just drive around and have a chat,'" Corden recalled with a laugh. "I went, 'Oh, right. It's just, we call it Carpool Karaoke, so without that...' And then I thought, I've just gotta go. I've just gotta jump into it. Even if this bit is just me singing to Mariah Carey, it's still on the show. It may not be the recurring bit that we hope it is, but it's still probably on the show."
Indeed, it only took one minute for Carey to declare "I'm not singing today, I was up all night!" in the edited package. Watch below.
The 46-year-old superstar eventually gave in to Corden's charm, gamely singing along to "Always Be My Baby," "Vision of Love," "Thirsty," and Ol' Dirty Bastard's "Fantasy," even showing off her British accent between tracks.
"To her credit, she got involved and it was wonderful," Corden said.
Only a few short months after its debut, Carpool Karaoke has already become a celeb favorite, booking superstars like Adele, Justin Bieber, Jennifer Lopez, Elton John, Sia and more. Even Julia Roberts and George Clooney took a spin in Corden's car recently, crashing Gwen Stefani's session. See how the epic shoot came together in the player below.