Guests Rob Gronkowski, Eva Longoria. Weezer and ZZ Top perform as WeeZ Top on the inaugural "Mash Up Mondays"

Lauren Cohan, Interview and Music from Jeff Bridges

Jennifer Lopez, Keith Urban, Harry Connick Jr., Ryan Seacrest (American Idol (2002)); Eric André (Man Seeking Woman (2015)); Keith Urban performs.

President Barack Obama; Sean Penn (The Gunman (2015)). Also: "Earth Wind and Fire" perform.

Zooey Deschanel, Guillermo Diaz, Charlie Wilson.

Vin Diesel. Music from Van Halen.

Kurt Russell, Jeff Ross. Music from Van Halen.

Dwayne Johnson, Rihanna. Music from Death Cab for Cutie.

Jason Statham (Fast & Furious 7 (2015)); NBA analyst Jalen Rose. Also: Brian Wilson performs.

Cobie Smulders, Austin BBQ Chef Aaron Franklin. Musical guest Chic.

Tim Allen, Kiernan Shipka. Musical guest Drew Holcomb and the Neighbors.

Scripps National Spelling Bee Champions 13-year-old Vanya Shivashankar from Kansas and 14-year-old Gokul Venkatachalam from Missouri, Music from Hiatus Kaiyote.

Bill O'Reilly, Kermit the Frog and Miss Piggy. Music from Robin Thicke.

Actor Bill Murray; Ryan Adams performs; ballet dancer Misty Copeland performs.

Rapper Jay Z, Tracy Morgan, music from Usher, Nas, and Jay Z. Donald Trump was originally scheduled to appear but canceled, he was replaced with Tracy Morgan. Musical guest was originally TIDAL X: 1020.

Actor Michael J. Fox appears with Christopher Lloyd in a Back to the Future skit honoring "Back to the Future Day" October 21, 2015. Democratic Presidential candidate Bernie Sanders discusses his campaign with Jimmy.

Actor Bradley Cooper, Joy Behar. Music from Esperanza Spalding. Paul Shaffer sits in with Cleto and the Cletones.

Radio personality Howard Stern, Public Enemy performs.

Liam Hemsworth (The Hunger Games: Mockingjay - Part 2 (2015)); Tracee Ellis Ross (Black-ish (2014)). Also: Jewel Kilcher and "Kool and The Gang" perform as "Jewel and the Gang" on "Mash Up Monday".

Melissa McCarthy ("Mike and Molly" (2010)). Also: One Direction perform and are interviewed.

Adam Sandler, Taylor Lautner, Luke Wilson, Terry Crews, Jorge Garcia and Rob Schneider (The Ridiculous 6 (2015)). Also: Fall Out Boy and Boyz II Men perform as "Fall Out Boys II Men" on "Mash Up Monday".

(RED) Shopathon for World AIDS Day with Olivia Wilde, Bono, Scarlett Johansson, Snoop Dogg, Matt Damon and more, Music from The Killers.

Director Quentin Tarantino and the cast of The Hateful Eight (2015), including Samuel L. Jackson, Kurt Russell, Jennifer Jason Leigh, Walton Goggins, Tim Roth, Michael Madsen and Bruce Dern. Also: Rick Ross performs.

Republican presidential candidate Donald Trump. Also: Gary Clark Jr. performs.