Junichiro Koizumi, one of the most popular politicians in recent decades, has kept a low profile since stepping down as prime minister in September 2006 and retiring from politics after the Aug. 30 election.

But the charismatic Koizumi's voice will stage a comeback of sorts — as that of a doyen to Ultraman — when "Dai-Kaiju Battle: Ultra Ginga Densetsu, The Movie" ("Great Monster Battle: Ultra Galaxy Legend, The Movie"), hits the silver screen Dec. 12.

Koizumi, a kabuki fan and eloquent speaker, will provide the voice for Ultraman King, a legendary elder of the gigantic Ultraman, who came to Earth to defend humans from space monsters.

"We asked Mr. Koizumi to play the role because Ultraman King is an elder of Ultraman, and because he delivers a speech in the movie," producer Akimoto Okagawa of Tsuburaya Productions said.

"Mr. Koizumi led the country. His voice is persuasive and (has the tone) of an experienced man," Okagawa said.

Koizumi first rejected the offer but changed his mind when his son, Shinjiro, a rookie Lower House member, urged him to play the role, saying he liked watching Ultraman when he was a child, according to Okagawa.

"Mr. Koizumi also watched the TV series, together with Shinjiro. He remembers and can sing the song of 'Ultraman Taro,' " Okagawa said. The latest installment in the space hero series will be distributed by Warner Bros. Entertainment Inc.