John Noble, born 20 August 1948, is an Australian actor whose career spans decades of work in film, television, and video games, including a significant number of roles in animation and voice-over. While he is perhaps best known internationally for his live-action performances as Denethor in the Lord of the Rings film trilogy and Dr. Walter Bishop on the science fiction series Fringe, Noble has also established a strong presence in the world of voice acting, particularly within genre animation and video game properties.

Noble has voiced prominent characters in several animated series and films, often bringing his distinctive voice to powerful antagonists. One of his notable voice roles is Unicron, a planet-sized transformer and a major villain, in the animated series Transformers: Prime and its subsequent television film conclusion Transformers Prime Beast Hunters: Predacons Rising. His work in the DC Comics animated universe includes voicing the villain Brainiac in the 2013 film Superman: Unbound. He also performed the voice of the Dragon Spirit in the 2010 film The Last Airbender. His voice acting extends to the role of the Diviner in the animated series Star Trek: Prodigy. In live-action television, he has voiced characters as well, such as the demon Mallus in DC's Legends of Tomorrow.

His voice work is also prominent in the video game industry. He provided the voice for the Scarecrow in the critically acclaimed Batman: Arkham Knight and portrayed Leland Monroe in the interactive crime drama L.A. Noire.

Regarding the specific role of Caliban in the series Cowboy Bebop, John Noble portrays this character in the 2021 live-action Netflix adaptation of the original anime series. The role of Caliban is one of the leaders, known as an Elder, of the powerful Red Dragon Crime Syndicate. It is important to note that this performance is in a live-action reimagining, not an animated or voice-over role in the original 1998 anime series.