After Fallon asked Timberlake what he's been up to, the 35-year-old artist replied, "Well, I recently voted. It was super quiet and under the radar."
On Monday, Timberlake voted in his hometown of Memphis, Tennessee. In a good-faith effort to encourage people to vote, the singer snapped a selfie while casting his ballot, which some believed was a violation of state election law. However, the Shelby County District Attorney's office later said they would not be investigating.
When asked if he had any advice for viewers when it came to voting, Timberlake looked directly into the camera to address those watching at home.
"Get out and vote," Timberlake said to a chorus of cheers from the audience. "But, uh, don't take a picture of yourself in there."
The interview soon turned to Timberlake's work on Trolls, where he was an executive music producer, as well as a voice actor alongside co-stars Anna Kendrick, James Corden, Gwen Stefani and Zooey Deschanel.
"They asked me to produce the music and coach these 'actors' on how to sing," Timberlake said incredulously, "and I was like, 'All these people know how to sing, man.'"
"So, basically, I'm just taking credit for all of their genius," he added with a smile. "Thanks!"
However, there's no denying Timberlake's catchy contribution to the soundtrack, "Can't Stop the Feeling!" has taken the country by storm since he debuted it in May. But the hit single wouldn't have happened without a few important conditions.
"He's a good dude," Fallon said, smiling. "I like that guy."
As the interview came to an end, Fallon surprised his audience with a massive pizza party, bringing box upon box out on stage and allowing everyone to come up and eat a slice with the superstar besties.
Finally, the two put their friendship to the test by asking each other questions from Fallon's “Best Friends Box." The challenge, which is somewhat like the Newlywed Game, shined an interesting light on their relationship.
As it turns out, their preferred mode of transportation when hanging out together is a tandem bike (because of course it is), and Timberlake's favorite childhood sitcom was Cheers (not Gilmore Girls, which is what Fallon guessed, but Timberlake said it was a close second).
Finally, the game ended with them performing a duet of the song they "always end up singing together" when they hang out: "I'm Keeping Your Poop (In a Jar)" by Hayseed Dixie. Seriously.
However, not wanting to go out on that note, they closed the segment out with a sweeter duet of the 1982 hit "Africa" by Toto, and it was adorable.
Recently, ET caught up with Timberlake at the premiere of Trolls, where he opened up about how much his little boy already loves the movie and can recognize his daddy's character. Check out the video to hear more.