Watch Justin Timberlake and Jimmy Fallon Sing at Summer Camp on 'The Tonight Show'

Andrew Lipovsky/NBC

Pals Timberlake and Jimmy Fallon returned to Camp Winnipesaukee to sing along to an Alanis Morissette tune.

Justin Timberlake stopped by The Tonight Show on Wednesday to reminisce about his days at summer camp. 

Pals Timberlake and Jimmy Fallon returned to Camp Winnipesaukee in a continuation of their earlier Late Night bits, when the two flashed back to 1980s and '90s camp memories. 

In the newest Tonight Show bit, the two friends talk about what they will be for Halloween — Steve Urkel? Zack Morris? For Timberlake, it's Blossom. 

Like the previous camp flashbacks, they then turned to singing along to the song they heard on the radio that day, this time "Ironic" by Alanis Morissette

"But we have to keep it down," they agreed, since it was lights out in the cabin. So the two sang the tune in whispered voices until the chorus, which is when camp counselor Mr. Fletcher (played by Tonight Show writer A.D. Miles) interrupted: "You two potato heads need to go to sleep!” he yelled, threatening to take away their Snack Shack privileges.

Once Fletcher left the cabin, Timberlake couldn't keep a straight face, laughing into his flashlight, before they broke into song again. The counselor returned to keep his word about taking away their snacks, but "what about s’mores and Tootsie Rolls?" asked Fallon. 

"If you hike your shorts up any higher we’re gonna see s’more of your Tootsie Roll,” joked Timberlake, as he shot water at the counselor with his water gun.

Eventually, the two campers agreed to go to sleep. "Hey, Jimmy, best friends forever?" Timberlake said, earning an “aww” from the audience.

The duo have plenty of experience performing together. The two friends kicked off their Camp Winnipesaukee bit in 2013 when Fallon was still at Late Night, singing Hootie & the Blowfish songs as young kids at summer camp. 

Timberlake and Fallon have also sung a barbershop quartet version of "Sexy Back," acted out the "Evolution of End Zone Dancing" on Fallon's Late Night, hosted the Barry Gibbs Talk Show on SNL, along with several iterations of their "History of Rap." Timberlake even acted as the official judge for the Lip Sync Battle between Fallon and Ellen DeGeneres last September. 

Timberlake is a star in the animated Trolls film, set to hit theaters Nov. 4. He also produced music for the film's soundtrack, including his original song "Can't Stop the Feeling."

See the video below.