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

Pour It Out with Margot Robbie
Pour It Out with Margot Robbie
Ellen Looks for the Mystery Celebrity Hiding in Her Audience
Ellen Looks for the Mystery Celebrity Hiding in Her Audience
Try Not to Laugh Challenge with Benedict Cumberbatch
Try Not to Laugh Challenge with Benedict Cumberbatch
Avengers Infinity War Cast Will Crack You Up
Avengers Infinity War Cast Will Crack You Up
‘Pretty Woman’ Cast Reunites 25 Years Later | TODAY
‘Pretty Woman’ Cast Reunites 25 Years Later | TODAY
Ryan Reynolds Has Had Enough of 'Frozen'
Ryan Reynolds Has Had Enough of 'Frozen'
Justin Timberlake & Anna Kendrick: Toy Shop Prank
Justin Timberlake & Anna Kendrick: Toy Shop Prank
Musical Genre Challenge with Miley Cyrus
Musical Genre Challenge with Miley Cyrus
Late Late Live Tinder w/ Collin Martin
Late Late Live Tinder w/ Collin Martin
Midnight Snacks: Thanksgiving Dinner Pringles, Mac & Cheese Candy Canes
Midnight Snacks: Thanksgiving Dinner Pringles, Mac & Cheese Candy Canes
Name That Song Challenge with Blake Lively, Carrie Underwood and Henry Golding
Name That Song Challenge with Blake Lively, Carrie Underwood and Henry Golding
Best Friends Challenge with Tina Fey (Extended Version)
Best Friends Challenge with Tina Fey (Extended Version)
Guest Host Chris Pratt Interviews Margot Robbie
Guest Host Chris Pratt Interviews Margot Robbie
Jimmy and Kevin Hart Ride a Roller Coaster
Jimmy and Kevin Hart Ride a Roller Coaster
Name That Song Challenge with Miley Cyrus
Name That Song Challenge with Miley Cyrus
Dance Battle with Jennifer Lopez
Dance Battle with Jennifer Lopez
Ellen and Jessica Biel Surprise Justin Timberlake!
Ellen and Jessica Biel Surprise Justin Timberlake!
Best Friends Challenge with Ariana Grande
Best Friends Challenge with Ariana Grande
Hashtags: #WhyIGotFired
Hashtags: #WhyIGotFired
David Blaine Shocks Jimmy and The Roots with Magic Tricks
David Blaine Shocks Jimmy and The Roots with Magic Tricks
Best Son Challenge with Rob Lowe and His Sons
Best Son Challenge with Rob Lowe and His Sons
Box of Lies with John Cena
Box of Lies with John Cena
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
One Word Songs with Meghan Trainor
One Word Songs with Meghan Trainor
Pour It Out with Chrissy Teigen
Pour It Out with Chrissy Teigen
Best Friends Challenge with Mark Ruffalo
Best Friends Challenge with Mark Ruffalo
True Confessions with Matthew McConaughey
True Confessions with Matthew McConaughey
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
Wheel of Musical Impressions with Céline Dion
Wheel of Musical Impressions with Céline Dion
Emma Stone Takes Buzzfeed's
Emma Stone Takes Buzzfeed's "Which Spice Girl Are You?" Quiz
Best Friends Challenge with Demi Lovato
Best Friends Challenge with Demi Lovato
Best of Justin Timberlake on The Tonight Show
Best of Justin Timberlake on The Tonight Show
Jimmy Interviews the Biggest Boy Band on the Planet BTS
Jimmy Interviews the Biggest Boy Band on the Planet BTS
Charades with Jessica Biel, Matt Bomer and Kelsea Ballerini
Charades with Jessica Biel, Matt Bomer and Kelsea Ballerini
Nick Jonas and Priyanka Chopra Made Their Own Couple Nickname
Nick Jonas and Priyanka Chopra Made Their Own Couple Nickname
Jamie Foxx Has Footage of Whitney Houston Singing Karaoke (Uncut Version)
Jamie Foxx Has Footage of Whitney Houston Singing Karaoke (Uncut Version)
Justin Timberlake Has a Silent Interview with Jimmy Fallon
Justin Timberlake Has a Silent Interview with Jimmy Fallon
Dance Battle with Blake Lively
Dance Battle with Blake Lively
Best Friends Challenge with Justin Timberlake
Best Friends Challenge with Justin Timberlake
Emma Stone's Favorite Part of Her Oscar Win Was Leonardo DiCaprio
Emma Stone's Favorite Part of Her Oscar Win Was Leonardo DiCaprio
Wheel of Musical Impressions with Melissa Villaseñor
Wheel of Musical Impressions with Melissa Villaseñor
Slow Turn, Tiny Nod with Justin Timberlake
Slow Turn, Tiny Nod with Justin Timberlake
"Evolution of Hip-Hop Dancing" (w/ Jimmy Fallon & Will Smith)
A-to-Z with Rami Malek
A-to-Z with Rami Malek
Kendall Jenner on Justin Bieber and Hailey Baldwin's Engagement
Kendall Jenner on Justin Bieber and Hailey Baldwin's Engagement
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
Robert Downey Jr. & Tom Holland on Spider-Man: Homecoming
Robert Downey Jr. & Tom Holland on Spider-Man: Homecoming