Jiro Dan (団 時朗, Dan Jirō; January 30, 1949 – March 22, 2023) was a Japanese actor, singer, and model best known for his role as Hideki Go/Ultraman Jack in The Return of Ultraman, making guest appearances in subsequent Ultraman productions as well. His real name was Hideo Murata (村田 秀雄). He was born in Kyoto and graduated from Heian High School.
Source: “Jirō Dan”, English Wikipedia (CC BY-SA 4.0), excerpt