'N Sync founding member Chris Kirkpatrick described to CNN what it was like working with him then: "It's almost like he is a perfectionist, but there's no work involved. You know, it's really just boom, boom, done. It's like, 'There it is.' One take Timberlake.'"
Timberlake's writing skills were getting him noticed by other big acts, too. Michael Jackson wanted "Gone," a JT-penned 'N Sync song from their last album, "Celebrity," Timberlake's manager Johnny Wright told CNN.
"We were at the Rock and Roll Hall of Fame and Michael's people came and they said, 'Hey, you know, I think Michael wants to record that record.' I looked at Justin and I was like, You're not giving that record away, because I knew how important that record was to him and what it meant for him as a writer to finally get songs."
But by 2002, Justin's high-profile relationship with Britney Spears was falling apart and 'N Sync went on hiatus.
"Everybody was kind of figuring out, 'What are we gonna do for the next six months?'" Wright recalled. "And then Justin kind of tapped me and said, "I know what I'm gonna do." He says, "I've had this music inside of me for quite a while. I'm gonna take this time and I'm gonna go make a record."
Then Justin launched the solo career that would define his next decade.
His debut album "Justified," which spawned hits like "Rock Your Body," "Cry Me a River," and "Like I Love You," soon became hot enough to land him on the biggest stage of all.
Super Bowl XXXVIII was broadcast live on February 1, 2004, from Houston on CBS. As "Billboard"'s Gallo remembers it, "Justin Timberlake is at the Super Bowl performing with Janet Jackson and he reaches over and he pulls away her top and he has now, apparently, committed the crime of the century."
A swift apology put Justin back on track, and his star continued to rise.
His sophomore album, the club-friendly "Future Sex/LoveSounds" gave us hits (and new vernacular) like "Sexy Back" and "What Goes Around ... Comes Around" in 2006.
That was the last new music we'd hear from Timberlake until now, but in the meantime, his career would explode from Grammys to Emmys, music to movies, including the Academy Award-nominated "The Social Network." He began investing in business ventures that interested him, became a must-see host of "Saturday Night Live," and has shot films with major stars like last year's "Trouble with Curve" with Clint Eastwood, and the upcoming Coen Brothers' "Inside Llewyn Davis," and "Runner, Runner" with Ben Affleck.
Then came the last six months.
A fall wedding in Italy to actress and Hollywood crush Jessica Biel landed Timberlake back on magazine covers and back into water cooler conversation.
He followed that up with the new album, released March 19, led by the single "Suit & Tie," featuring Jay-Z. "The 20/20 Experience," which was completed in just four weeks, according to Wright, is currently on pace to sell 850,000 to 900,000 copies in its first week, likely knocking Mumford & Sons' "Babel" out of the top-selling slot of the year.
On top of that, it was just announced that Timberlake will follow up the soulful album with an additional 10 tracks later this year.
An immensely successful "SNL" hosting gig preceded a week of instantly viral and hilarious appearances on "Late Night with Jimmy Fallon."
Not only is Timberlake making what Kirkpatrick refers to as "grown folks music," he's also "doing a great job at reinventing himself," the former bandmate said.
"The one thing I always say about Justin is he always had an eye and an ear for what's next. Not what's cool, but what's next."