John Knell is the professional pseudonym of John Michael Tatum, an American voice actor born on May 25, 1976, in McKinney, Texas. He is primarily known for his extensive work in English-language dubs of Japanese anime, most frequently through his long-standing association with Funimation.

Tatum began his voice acting career in 2005 when he was discovered by an ADR director who cast him as Rikichi in the series Samurai 7. Over the years, he has portrayed a wide range of prominent characters. One of his notable roles is Alphonse Medici Borgiani, a secondary character in the series Dance in the Vampire Bund. His other major voice roles include Kyoya Ootori in Ouran High School Host Club, Sebastian Michaelis in Black Butler, Erwin Smith in Attack on Titan, Eneru in One Piece, the personification of France in Hetalia: Axis Powers, and Rei Ryuugazaki in Free! – Eternal Summer.

Beyond voice acting, Tatum has also worked as an ADR (Automated Dialogue Replacement) director and script writer. From January 2010 to January 2014, he co-hosted a talk show titled That Anime Show alongside fellow voice actor Terri Doty. His career includes recurring collaborations with Funimation and OkraTron 5000, as well as frequent work with other voice actors such as Christopher Sabat, Colleen Clinkenbeard, and Monica Rial.