Jessica Biel and Jimmy Fallon try to guess Justin Timberlake's responses to a series of random questions in a competition to see who really knows him best.

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The Tonight Show Starring Jimmy Fallon features hilarious highlights from the show including: comedy sketches, music parodies, celebrity interviews, ridiculous games, and, of course, Jimmy's Thank You Notes and hashtags! You'll also find behind the scenes videos and other great web exclusives.

Best Friends Challenge with Justin Timberlake and Jessica Biel
http://www.youtube.com/fallontonight

#BestFriendsChallenge
#JustinTimberlake
#JessicaBiel

Ellen Looks for the Mystery Celebrity Hiding in Her Audience
Ellen Looks for the Mystery Celebrity Hiding in Her Audience
Charades with Gal Gadot and Miley Cyrus
Charades with Gal Gadot and Miley Cyrus
Will Smith and Ellen Play 5 Second Rule
Will Smith and Ellen Play 5 Second Rule
Lip Sync Charades with Reese Witherspoon, Lenny Kravitz and Zoë Kravitz
Lip Sync Charades with Reese Witherspoon, Lenny Kravitz and Zoë Kravitz
What's the Most Interesting Thing About You?
What's the Most Interesting Thing About You?
Take A Break - Walmart
Take A Break - Walmart
The Best of Celebrities Answer
The Best of Celebrities Answer "Ellen's Burning Question" 2
Mark Wahlberg Surprises Viral Adoption Family
Mark Wahlberg Surprises Viral Adoption Family
Try Not to Laugh Challenge with Benedict Cumberbatch
Try Not to Laugh Challenge with Benedict Cumberbatch
Jessica Biel Talks Smack About Her Two Year Old
Jessica Biel Talks Smack About Her Two Year Old
Charades with Kit Harington, Rose Byrne and Blake Shelton
Charades with Kit Harington, Rose Byrne and Blake Shelton
David Blaine Shocks Jimmy and The Roots with Magic Tricks
David Blaine Shocks Jimmy and The Roots with Magic Tricks
The Best of Ellen Scares Celebrities 2018
The Best of Ellen Scares Celebrities 2018
True Confessions with Matthew McConaughey
True Confessions with Matthew McConaughey
Will Ferrell and Chad Smith Drum-Off
Will Ferrell and Chad Smith Drum-Off
Charades with Jessica Biel, Matt Bomer and Kelsea Ballerini
Charades with Jessica Biel, Matt Bomer and Kelsea Ballerini
Best Friends Challenge with Ariana Grande
Best Friends Challenge with Ariana Grande
Uncomfortable Moments That Aired On Ellen
Uncomfortable Moments That Aired On Ellen
Name That Song Challenge with Blake Lively, Carrie Underwood and Henry Golding
Name That Song Challenge with Blake Lively, Carrie Underwood and Henry Golding
Nicki Minaj, Fortnite, and More Ideas for Kids' Halloween Costumes!
Nicki Minaj, Fortnite, and More Ideas for Kids' Halloween Costumes!
Cole Sprouse Had A Childhood Crush On His 'Friends' Co-Star
Cole Sprouse Had A Childhood Crush On His 'Friends' Co-Star
Dance Battle with Jennifer Lopez
Dance Battle with Jennifer Lopez
Loaded Questions with Chrissy Teigen
Loaded Questions with Chrissy Teigen
Best Friends Challenge with Tina Fey (Extended Version)
Best Friends Challenge with Tina Fey (Extended Version)
Jamie Foxx Has Footage of Whitney Houston Singing Karaoke (Uncut Version)
Jamie Foxx Has Footage of Whitney Houston Singing Karaoke (Uncut Version)
Box of Lies with John Cena
Box of Lies with John Cena
Bradley Cooper and Jimmy Can't Stop Laughing (Uncut Version)
Bradley Cooper and Jimmy Can't Stop Laughing (Uncut Version)
Box of Lies with Cardi B
Box of Lies with Cardi B
Emma Stone Takes Buzzfeed's
Emma Stone Takes Buzzfeed's "Which Spice Girl Are You?" Quiz
One Word Songs with Meghan Trainor
One Word Songs with Meghan Trainor
The Whisper Challenge with Margot Robbie
The Whisper Challenge with Margot Robbie
Justin Timberlake Has a Silent Interview with Jimmy Fallon
Justin Timberlake Has a Silent Interview with Jimmy Fallon
Mila Kunis Spent Her Honeymoon in an RV Park with Ashton Kutcher's Parents
Mila Kunis Spent Her Honeymoon in an RV Park with Ashton Kutcher's Parents
Name That Song Challenge with Jared Leto
Name That Song Challenge with Jared Leto
Bradley Cooper Leaves with Jimmy Mid-Interview to Check if He's Wearing a Repeat Suit
Bradley Cooper Leaves with Jimmy Mid-Interview to Check if He's Wearing a Repeat Suit
Bradley Cooper Had Instant Chemistry with Lady Gaga When They Sang
Bradley Cooper Had Instant Chemistry with Lady Gaga When They Sang
Nick Jonas and Priyanka Chopra Made Their Own Couple Nickname
Nick Jonas and Priyanka Chopra Made Their Own Couple Nickname
Kendall Jenner on Justin Bieber and Hailey Baldwin's Engagement
Kendall Jenner on Justin Bieber and Hailey Baldwin's Engagement
Barbra Streisand Carpool Karaoke
Barbra Streisand Carpool Karaoke
Best Friends Challenge with Justin Timberlake
Best Friends Challenge with Justin Timberlake
Best of Justin Timberlake on The Tonight Show
Best of Justin Timberlake on The Tonight Show
Kim Kardashian Picked Spinach out of Ashley Graham's Teeth
Kim Kardashian Picked Spinach out of Ashley Graham's Teeth
Emma Stone's Favorite Part of Her Oscar Win Was Leonardo DiCaprio
Emma Stone's Favorite Part of Her Oscar Win Was Leonardo DiCaprio
Lip Sync Battle with Tiffany Haddish
Lip Sync Battle with Tiffany Haddish
Rami Malek Discusses His Freddie Mercury Transformation
Rami Malek Discusses His Freddie Mercury Transformation
A-to-Z with Rami Malek
A-to-Z with Rami Malek
Travis Scott Shows Off His Broadway Musical Abilities
Travis Scott Shows Off His Broadway Musical Abilities
Thank You Notes: Pumpkin Beer, Veterans Day
Thank You Notes: Pumpkin Beer, Veterans Day
Matt Czuchry Confronts Jimmy About Being Team Jess over Team Logan
Matt Czuchry Confronts Jimmy About Being Team Jess over Team Logan
John Krasinski Pranks Jimmy Kimmel in Brooklyn
John Krasinski Pranks Jimmy Kimmel in Brooklyn