Fallon took The Tonight Show to Central Park on Thursday for the first time ever, shooting an episode on an outdoor stage in the middle of the historic New York City locale, and to celebrate the special occasion he teamed up with the singer for a goofy pre-taped segment.
Donning bad wigs, laughably fake mustaches, dark glasses and loose-fitting black suits, Fallon and Bieber headed out into Central Park for a segment the host called "Musical Photobomb."
Both stars wore earpieces playing Bieber's hit "What Do You Mean?" and proceeded to lip sync and dance to a song no one else could hear behind and around unaware and unsuspecting random park goers.
While Fallon in disguise still looks very much like himself, Bieber actually managed to disappear into his hilariously bad get up, which made him look remarkably like a slender mid-1970s Sonny Bono.
From dancing in the background behind a group of people enjoying a picnic to busting out choreographed moves on some park steps next to a man jamming on a guitar, the pair made total spectacles of themselves, and yet managed to remain relatively unnoticed.
It wasn't until the very end of their day out -- which seemed to take them throughout the entire park -- that Bieber and Fallon pulled off their floppy wigs and poorly attached mustaches to reveal their true identities, at which point they posed for photos with his legion of fans.
The sketch was shot nearly a month ago, when photos of Fallon and Bieber in their surprisingly successful disguises began popping up on social media.
However, this wasn't the first time the "Sorry" singer managed to go unrecognized while out and about in New York City. Back in July 2016, Pokemon Go fans were so excited about the captivating new game that they didn't realize that Bieber was playing right alongside them -- and that was without him even wearing a disguise at all!
37PHOTOS
Justin Bieber's Style Transformation
See Gallery
Justin Bieber's Style Transformation
March 2009
A baby-faced Justin Bieber makes his way along the Nickelodeon-inspired orange carpet alongside Usher.
Photo Credit: Jason Merritt, Getty Images
September 2009
Justin adding a bit more red to the red carpet with a boyish look at the 2009 MTV Movie Awards.
Photo Credit: Michael Loccisano, Getty Images
December 2009
Bum leg and all, Justin is still all smiles in denim at the 2009 Z100 Jingle Ball.
Photo Credit: Jim Spellman, WireImage/Getty Images
January 2010
Justin's just chillin' at the 52nd Annual Grammy Awards.
Photo Credit: John Shearer, WireImage/Getty Images
March 2010
Justin keeping it simple at Nickelodeon's 23rd Annual Kids Choice Awards; loving the hint of neon to finish off the all black look.
Photo Credit: Larry Vusacca, Getty Images
May 2010
Justin cleans up nicely in a tuxedo at the White House Correspondents' Association dinner.
Photo Credit: Brendan Hoffman, Getty Images
May 2010
Justin sports a black and white look, but adds his signature dog tags to spice things up at the 2010 KIIS FM's Wango Tango event.
Photo Credit: Angela Weiss, Getty Images
May 2010
Some men are too chicken to wear pink, but not Justin! He's all about the color while promoting his album "My Worlds" in Tokyo. We can dig it.
Photo Credit: Jun Sato, WireImage/Getty Images
June 2010
With a crowd of adoring fans behind him at the 21st Annual MuchMusic Video Awards, Justin poses on the red carpet in grey blazer and light blue denim.
Photo Credit: George Pimentel, WireImage/Getty Images
June 2010
Justin keeping his cool on stage while performing in a purple and white look.
Photo Credit: Mark Von Holden, WireImage/Getty Images
September 2010
Justin gets a little rebellious on us with an all-black ensemble and a few metallic accessories at the 2010 MTV Video Music Awards.
Photo Credit: Steve Granitz, WireImage/Getty Images
October 2010
Justin sports our favorite trend - leather, during an appearance at Barnes & Noble at The Grove.
Photo Credit: Frederick M. Brown, Getty Images
November 2010
Accessorized in awards, Justin is seen in all black while in the press room at the 2010 American Music Awards.
Photo Credit: Jon Kopaloff, FilmMagic/Getty Images
November 2010
Channeling Michael Jackson with this grey leather, Justin attends "The World's The Collection" photocall.
Photo Credit: Carlos Alvarez, Getty Images
December 2010
Illuminated in light and studded at the shoulders, Justin performs at the Q102 Jingle Ball.
Photo Credit: Jeff Fusco, Getty Images
January 2011
Justin keeping a causal edge to his red carpet look at the 68th Annual Golden Globe Awards.
Photo Credit: George Pimentel, WireImage/Getty Images
February 2011
Justin smiling ear to ear in his army-inspired look while on set for New.Music.Live promoting his new film.
Photo Credit: George Pimentel, WireImage/Getty Images
February 2011
Seemingly torn between looks, Justin poses for photos at the UK Premiere of "Never Say Never" in a half denim and half tuxedo look.
Photo Credit: Ian Gavan, Getty Images
February 2011
Adding a little color to this all black look, Justin tosses in a red pocket square to liven things up at the Vanity Fair Oscar Party.
Photo Credit: Craig Barritt, Getty Images
May 2011
We're loving this metallic gold blazer that Justin wore to the 2011 Billboard Music Awards.
Photo Credit: Kevin Mazur, WireImage/Getty Images
June 2011
Moving into a more slimmer-fitting style, Justin makes his way off-stage in a blue blazer and white denim at the 2011 MTV Movie Awards.
Photo Credit: Jeff Kravitz, WireImage/Getty Images
June 2011
Messy hair and pink inspired look, Justin works the camera at the 22nd Annual MuchMusic Video Awards.
Photo Credit: George Pimentel, Getty Images
June 2011
Texture from head to toe, Justin basks in the sunlight at the 2011 BET Awards.
Photo Credit: Jason LaVeris, FilmMagic/Getty Images
July 2011
Showing his love of sport, Justin arrives in pitcrew attire to the 2011 ESPY Awards.
Photo Credit: Kevin Mazur, WireImage/Getty Images
August 2011
Slimming down the glasses and showing his love of both designer and print, Justin poses for cameras at the 2011 MTV Video Music Awards.
Photo Credit: Jason Merritt, Getty Images
September 2011
Collar popped and sleeves rolled up; Justin poses for photos at the Dolce & Gabbana Boutique.
Photo Credit: Eugene Gologursky, Getty Images
November 2011
Justin looking preppy on the red carpet of the 2011 MTV Europe Music Awards.
Photo Credit: Ian Gavan, Getty Images
November 2011
At the 2011 Bambi Award Ceremony Justin looked simple and stylish but we think he may have forgotten to take off one tag on his sneakers.
We're not really loving this look; after all what is Justin Bieber without his signature hair?
Photo Credit: Cindy Ord, Getty Images
November 2011
When Justin and Selena separated we have to admit we are quite sad especially after seeing images like this; the two were a picture of perfection at the 2011 American Music Awards.
Photo Credit: Steve Granitz, WireImage/Getty Images
January 2012
We know he's been a huge fan of leather but for us this blue jacket takes the cake; loving his look at the NRJ Music Awards.
Photo Credit: Pascal Le Segretain, Getty Images
May 2012
Looking bright and cheerful, Justin stops for photographs at the Billboard Music Awards.
