Terence Stamp played the voice role of the Prophet of Truth in Halo 3 replacing Michael Wincott who played the role for Truth in Halo 2.
Alongside Halo 3, Stamp also has portrayed several other characters, many of them being villains. He has also been nominated for an Academy Award.
In live action films, Stamp portrayed General Zod in Superman II, Chancellor Valorum in Star Wars Episode I: The Phantom Menace, Stick in Elektra, Siegfried in Get Smart, and other films such as Red Planet , Yes Man, and My Boss' Daughter.
Stamp also lent his voice in animated features and video games. In addition to Truth, Terence Stamp also played another key video game antagonist, Mankar Camoran, in the Elder Scrolls IV: Oblivion.
In the Halo 3 Legendary Edition bonus disc you can see him voice acting. He's talking as Truth on the part where you enter the control room of the Ark in Halo 3.