It all started in February 2004 when a gifted producer who called himself Danger Mouse edited a seamless mash-up of Jay-Z’s The Black Album with The Beatles’ “White Album.” Though it was created for fun, The Grey Album quickly went viral and became an underground sensation. Danger Mouse went on to major success as a producer and rapper and his oddball mash-up attracted attention from major names in big places.

Seeing dollar signs, MTV decided to put together a mash-up series that involved some of the biggest bands working with the hottest rappers. One of the first people the network approached was Jay-Z, who liked the idea. When the network asked him who he’d want to work with he answered, “Linkin Park.”

Jay-Z’s manager contacted the band, which was excited at the idea of working with the hip-hop entrepreneur. Nine months later, the two artists released the six-track EP Collision Course, which explored the creative possibilities of mashing up metal and rap.

As soon as Linkin Park’s co-vocalist Mike Shinoda heard that Jay-Z wanted to do a mash-up project with the band, he took the initiative and steered the project. “A lot of people were involved, but all the credit goes to Mike [Shinoda] on this one,” vocalist Chester Bennington told me in 2007. “He really put the whole thing together and got everyone excited about it.”

At the time, Linkin Park were on tour, and Shinoda had a laptop and some recording software in the back lounge of the bus. Using a cupulas and instrumentals he downloaded from the web, he worked around the clock and recorded demos for three of the mash-ups in less the two days. Then, he sent the files of the tracks to Jay-Z. When the rapper heard them, he picked up his cell phone and texted Shinoda, “Oh, Shit!” From there, it was on.

“We got on the phone with Jay and his people and I basically said that we should make an EP together and make it so good that MTV couldn’t possibly do a complete series because we had done it as it would set the bar too high,” Shinoda said. “So that’s what we did.”

When the project was originally proposed, no one realized that it put Shinoda right in his comfort zone. Back before Linkin Park formed, the rapper and vocalist used to sit at home and make mash-ups. Among his early efforts were mixes that featured Nine Inch Nails, Rage Against the Machine and the Jackson 5, with vocal tracks by Mobb Deep and Wu-Tang Clan. “That’s pretty much how I learned to produce when I was growing up,” he said. “I’d been doing this kind of stuff since the early ‘90s.”

Collision Course, which came out Nov. 30, 2004 featured major chunks of four songs from Linkin Park’s Hybrid Theory and three from Meteora mixed with two songs from The Black Album and one each from The Blueprint, Vol. 2..., Hard Knock Life and Vol. 3… Life and Times of S. Carter. Shinoda and Jay-Z exchanged files of ideas for the songs. Deciding they wanted the EP to feature new vocal takes instead of the ones on the already-released albums, Shinoda, Bennington and Jay-Z recorded their parts for the EP between July 16 and 19, 2004.

MTV, which was involved with the project along with Warner Bros., Machine Shop, Roc-A-Fella, Warner Bros and Def Jam, didn’t end up doing the mash-up series they had pitched. Instead, on Nov. 10, 2004, they aired MTV: Ultimate Mash-Ups: Jay Z vs. Linkin Park, which documented the creation of the project. A DVD that accompanied Collision Course, featured the MTV program, a documentary about the July 18 Linkin Park/Jay-Z concert at the Roxy Theater in West Hollywood and performances of all six songs on the EP.

While Jay-Z had collaborated with The Roots and R. Kelly and Linkin Park had worked with members of Staind, Orgy, X-Ecutioners, Deftones, Korn, Pharoahe Monch, KutMasta Kurt and others on their 2002 remix album Reanimation, Collision Course marked the first musical meeting between LP and Jay and both rock and rap fans responded to the inventive mash-ups they created. Collision Course entered the Billboard 200 at No. 1 and the single “Numb/Encore” won “Best Rap/Sung Collaboration” at the 2006 Grammy Awards.

Jay-Z, who had supposedly entered performance retirement, took the stage with Linkin Park at the Grammys to perform the Grammy-winning track. To pay tribute to Danger Mouse’s Grey Album and bring the project full-circle, they invited Paul McCartney to perform with them. The former Beatle accepted and Bennington and McCartney sang segments of The Beatles’ “Yesterday” while Jay interjected with “that’s right,’ “uh-huh,” and “yesterday.” For the appearance, Jay-Z wore a white suit with a black T-Shirt that depicted John Lennon and Bennington looked sharp in a jacket, slacks and white collared shirt.

Collision Course went platinum on July 19, 2005 and was registered double platinum by the RIAA on Aug. 15, 2017. While Jay-Z and Linkin Park haven’t worked together since, Jay was the executive producer of the album by Shinoda’s side project Fort Minor, of The Rising Tied, which came out in 2015.

Loudwire contributor Jon Wiederhorn is the co-author of Louder Than Hell: The Definitive Oral History of Metal, as well as the co-author of Scott Ian’s autobiography, I’m the Man: The Story of That Guy From Anthrax, and Al Jourgensen’s autobiography, Ministry: The Lost Gospels According to Al Jourgensen and the Agnostic Front book My Riot! Grit, Guts and Glory.