Javier "Harvey" Guillén (pronounced [ɡiˈʝen]; born (1990-05-03)May 3, 1990)^[2][3] is an American actor. He is best known for his role as the human familiar Guillermo de la Cruz in the 2019 television series What We Do in the Shadows.^[4][5]

Guillén has appeared in recurring roles on a number of television series, such as Alistair Delgado on Huge (2010), Cousin Blobbin on The Thundermans (2013–2018), George Reyes in Eye Candy (2015), and Benedict Fenwick on The Magicians (2017–2018).^[6] He also appeared in the 2013 film The Internship.^[7]

Beginning in 2019, Guillén has played the role of Guillermo, the vampires' human familiar, in the FX television series What We Do in the Shadows.^[8] He was also set to appear in Quibi's science fiction drama series Don't Look Deeper,^[9] before the platform shut down in December 2020.

Guillén has received considerable acclaim for his role as Guillermo. TheWrap included Guillén in a list of "2019 Emmy Contenders".^[10] Hank Steuver, in his review of What We Do in the Shadows in The Chicago Tribune, stated that Guillén "provides at least half the big laughs" in the show.^[8]

Guillén provides the voice of Funny the Magic House in Mickey Mouse Funhouse. Guillén played Nightwing in season 3 of Harley Quinn.^[11]

During 2022, Guillén also provided the voice for the comedic sidekick character Perrito in Puss in Boots: The Last Wish.^[12]

In 2023, Guillén appeared on The Late Show with Stephen Colbert where he appeared in a skit as Representative George Santos.^[13]

In 2024, Guillén reprises his role as Cousin Blobbin from The Thundermans in The Thundermans Return. He will also provide the voice of Odie in The Garfield Movie.

Guillén is the son of Mexican immigrants.^[14] He adopted the name Harvey when his teachers could not pronounce his first name.^[1]

Guillén is multilingual, and can speak Spanish, English, and Japanese;^[15] the last of which was due to a visit to Japan that lasted thirteen months.

He identifies as queer.^[16][17][18]