The casts of FBI and FBI: Most Wanted during a crossover event

Julian McMahon as Jess LaCroix, Roxy Sternberg as Sheryll Barnes, Miguel Gomez as Ivan Ortiz, Zeeko Zaki as Omar Adom 'OA' Zidan, and Missy Peregrym as Maggie Bell.

Photo: Mark Schfer/CBS.

Get ready for "All-FBI Tuesdays" on CBS!

By Nate Millado

FBI: International—the globe-trotting iteration of the popular franchise—kicks off Tuesday, Sept. 21, as part of a three-hour crossover premiere event! So you'll get introduced to the Fly Team's special agents with a little help from some friends, including FBI's OA (Zeeko Zaki) and Maggie Bell (Missy Peregrym) and FBI: Most Wanted's Jess LaCroix (Julian McMahon).

Of course, this isn't the first time we've seen our favorite characters from different shows cross paths. Watch rounds up some of our favorite crossover events!

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The FBI three-hour crossover event airs Tuesday, Sept. 21, 8-11 p.m. ET/PT on CBS.

Supergirl "Star-Crossed" andThe Flash "Duet"

\u200b Grant Gustin and Melissa Benoist strike a ballroom dance pose

Once more with feeling! The Flash's Barry Allen and Supergirl''s Kara sing and dance their way through this musical crossover.

Photo: Jack Rowand/The CW.

Kara (Melissa Benoist) and Barry (Grant Gustin) find themselves trapped in a musical and must sing and dance their way out of this alternate reality. Luckily for them (and us viewers), this dynamic duo is more than capable of tackling the demanding song-and-dance numbers. Their fellow Glee alum Darren Criss plays the crossover's big bad, the Music Meister.

Watch The Flashon The CW. Watch free next day on and The CW app.

Stream episodes of your favorite shows on Paramount+.

Hawaii Five-0 "Pa Make Loa" and NCIS: Los Angeles "Touch of Death"

Chris O'Donnell and and Scott Caan watch as LL COOL J and Daniel Dae Kim race away

When worlds collide! Hawaii Five-0 meets NCIS: Los Angeles.

Photo: Richard Cartwright/CBS.

Agents Sam Hanna (LL COOL J) and G. Callen (Chris O'Donnell) head to the Aloha State to help Five-0 nab prime suspect Dracul Comescu. The joint task force—with Detective Sergeant Danny Williams (Scott Caan) and Lieutenant Chin Ho Kelly (Daniel Dae Kim), in tow—travels from Hawaii to Los Angeles when the lead suspect in the case moves to the mainland with a deadly virus. Fun fact: "Pa Make Loa" in Hawaiian translates to "Touch of Death."

Watch NCIS: Los Angeles on CBS and streaming on Paramount+.

Stream all seasons of Hawaii Five-0 on Paramount+.

NCIS and NCIS: New Orleans "Pandora's Box Parts I and II"

Scott Bakula with Vanessa Ferlito and Wilmer Valderrama

NCIS Special Agents Dwayne Pride, Tammy Gregorio, and Nick Torres.

Photo: Skip Bolen/CBS.

Laissez les bons temps rouler ("let the good times roll") when the NCIS and NCIS: New Orleans teams join forces to track down a "how to be a terrorist" playbook—during Mardi Gras, no less, where everyone is masked!

Watch NCIS: Los Angeles on CBS and streaming on Paramount+.

Stream NCIS: New Orleans episodes on Paramount+.

Supergirl, Batwoman, The Flash, Arrow, and DC's Legends of Tomorrow "Crisis on Infinite Earths"

A group photo of the stars of The CW Arrowverse shows

Back row: Melissa Benoist as Kara/Supergirl, Brandon Routh as Ray Palmer/Atom, Stephen Amell as Oliver Queen/Green Arrow, Ruby Rose as Kate Kane/Batwoman, Chyler Leigh as Alex Danvers, Grant Gustin as The Flash, David Harewood as Hank Henshaw, Jesse Rath as Brainiac-5. Front row: Audrey Marie Anderson as Harbinger, Katherine McNamara as Mia, Caity Lotz as Sara Lance/White Canary, Tyler Hoechlin as Clark Kent/Superman, and Bitsie Tulloch as Lois Lane.

Photo: Katie Yu/The CW.

The CW's annual Arrowverse crossover—which unites all of the network's DC shows—is always an event. But the "Crisis on Infinite Earths" storyline, where our super friends unite to vanquish the Anti-Monitor—more than lived up to the hype, with long-lasting repercussions, fun cameos from other DC properties (hello, Man of Steel Brandon Routh and Ezra Miller Flash), and one shocking death (RIP Oliver Queen/Green Arrow).

Stream episodes of your favorite shows on Paramount+.

Watch The Flashon The CW. Watch free next day on and The CW app.

Watch Batwoman on The CW. Stream next day free only on and The CW app.

Hawaii Five-0 "Ihea 'oe i ka wa a ka ua e loku ana?" andMagnum, P.I. "Desperate Measures"

A scene from the Hawaii Five-0 and Magnum, P.I. crossover

Katrina Law as Quinn, Meaghan Rath as Tani Rey, Perdita Weeks as Juliet Higgins, Zachary Knighton as Orville 'Rick' Wright, and Jay Hernandez as Thomas Magnum.

Photo: Karen Neal/CBS.

Sure, Hawaii Five-0 characters have appeared on Magnum, P.I. before, but in this full-fledged crossover, McGarrett (Alex O'Loughlin) and co. reluctantly team up with Magnum (Jay Hernandez) and Higgins (Perdita Weeks) to recover a stolen list of undercover CIA agents.

Stream all seasons of Hawaii Five-0 on Paramount+.

Watch Magnum P.I. Fridays at 9 p.m. ET/PT on CBS and streaming on Paramount+.

Supernatural "Scoobynatural"

The stars of Supernatural animated as cartoon characters

The Winchester Bros. get animated for "Scoobynatural."

Photo: The CW/Warner Bros. Entertainment Inc.

On paper, the tonally different cartoon classic and the totally-not-for-kids Supernatural series shouldn't work—and yet the meta "Scoobynatural" episode hits you with the nostalgic feels. Sam (Jared Padelicki), Dean (Jensen Ackles), and Castiel (Misha Collins) are sucked into the 1970 Scooby-Doo, Where Are You! episode "A Night of Fright Is No Delight" and must help the Scooby Gang solve the mystery. Of course Dean (being Dean) calls "dibs on Daphne!"

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