--- ---  # J.K. Simmons to Join Cast of Disney's _Gravity Falls_ by [Joseph C. Lin](https://time.com/author/joseph-c-lin/) ## Joseph C. Lin Jun 12, 2015 4:00 PM UTC  The "author" and Grunkle Stan are seen in the "A Tale of Two Stans" episode of Gravity Falls The "author" and Grunkle Stan are seen in the "A Tale of Two Stans" episode of Gravity FallsDisney XD by [Joseph C. Lin](https://time.com/author/joseph-c-lin/) ## Joseph C. Lin Jun 12, 2015 4:00 PM UTC  J.K. Simmons during a recording session for Gravity Falls. Guy D'Alema—Disney Channel Disney XD’s Emmy-award winning _Gravity Falls_ left viewers with a major cliffhanger in its mid-season finale when it was revealed that Grunkle Stan (voiced by series creator Alex Hirsch) has a twin brother—who is the mysterious six-fingered author of the journals that have led twins Dipper (Jason Ritter) and Mabel Pines (Kristen Schaal) on supernatural misadventures in the fictional town of Gravity Falls, Oregon. The previously unseen brother will be voiced by Academy Award winner J.K. Simmons, in a recurring role on the series. Simmons isn’t a newcomer to voice work, having previously voiced characters on shows like _Kim_ _Possible;_ more recently, he served as the voice of Tenzin in _Legend of Korra_. His debut episode will be “A Tale of Two Stans,” premiering on July 13 on Disney XD. The episode will pick up where the mid-season finale ended and will also reveal the name of the Grunkle’s brother. Previous guest stars on _Gravity Falls_ have included Nick Offerman as the voice of a secret agent and [Neil deGrasse Tyson](http://time.com/3432721/neil-degrasse-tyson-gravity-falls-pig/) as the voice of a super-intelligent pet pig. ### Celebrities You Didn’t Know Were Voice Actors  John Oliver had a brief cameo on The Simpsons as Booth Wilkes-John, the Simpsons' British neighbor. Fox; Jamie McCarthy—Getty Images  Even though Benedict Cumberbatch can't pronounce the word penguin, he joins the cast of The Penguins of Madagascar as the voice of Agent Classified. Dreamworks; Jim Spellman—WireImage/Getty Images  30 Rock Star Scott Adsit lends his voice to the lovable robot Baymax in Disney's Big Hero 6 Disney; Alberto E. Rodriguez—Getty Images  Freddie Prinze Jr., the 90s heartthrob and movie star, is back to voice Kanan, a Jedi in Disney’s latest animated series, Star Wars Rebels. Lucasfilm/Disney XD; Frazer Harrison—Getty Images  Mark Hamill has had an impressive second act following Star Wars as a prolific and celebrated voice actor giving life to characters such as the Joker in Batman: The Animated Series and Fire Lord Ozai in Avatar: The Last Airbender. Fox; Tommaso Boddi—WireImage/Getty Images  Vin Diesel’s voice acting career consists of more than three words. In 1999, he was the voice of The Iron Giant in its eponymous movie. Warner Bros.; Anthony Harvey—Getty Images  Before they were comedic giants, Stephen Colbert and Steve Carell lent their voices to The Ambigiously Gay Duo, an animated comedy sketch that first got its start on The Dana Carvey Show before moving to Saturday Night Live. Everett; Jason Kempin—Getty Images  Jaleel White, the actor formerly known as Urkel, was the voice of Sonic the Hedghog in the 90s television show Adventures of Sonic the Hedgehog. DiC Enterprises; Imeh Akpanudosen—Getty Images  Reginald VelJohnson is best known for his nine seasons as Carl Winslow on Family Matters, but more recently he was the voice of Able, a mechanic and fatherly figure in Disney’s Tron: Uprising. Disney XD (2)  Darius McCrary, who played the older brother Eddie Winslow on Family Matters, was the voice of Jazz in the 2007 Transformers movie. Dreamworks; Frederick M. Brown—Getty Images  Will Friedle, who played the underachieving elder brother in Boy Meets World, has voiced a number of memorable characters such as Terry McGinnis, the titular character of Batman Beyond and Ron Stoppable in Kim Possible. Warner Bros.; Barry King—WireImage/Getty Images  Arrested Development star Jessica Walter currently voices Malory Archer in FX’s Archer, but back in the 90s, she was the voice of Dinosaurs matriarch Fran Sinclair. Jim Henson Productions; Alberto E. Rodriguez—Getty Images  Tim Curry lent his comedic talents to voice the eccentric Nigel Thornberry for five seasons of Nickelodeon’s The Wild Thornberrys. Paramount  Flea, the bassist for the Red Hot Chili Peppers, voiced the incoherent gibberish of the feral boy Donnie, in The Wild Thornberrys. Paramount  As if being on Star Trek: The Next Generation and Reading Rainbow weren’t enough, LeVar Burton was also the voice of Kwame on Captain Planet and the Planeteers. Hanna-Barbera; Albert L. Ortega—Getty Images  Bruce Willis had a brief voice acting cameo as the voice of Spike in the 2003 movie Rugrats Go Wild. Paramount; Jeffrey Mayer—WireImage/Getty Images J.K. Simmons to Join Cast of Disney's Gravity Falls ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/3918960/gravity-falls-jk-simmons/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/3918960/gravity-falls-jk-simmons/"},"headline":"J.K. 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