Young Japanese golf star and heartthrob Ryo Ishikawa has disappointed his legions of female admirers by announcing his engagement to his childhood sweetheart.

Nicknamed "The Bashful Prince", he stayed true to form with the announcement, giving scant details about his forthcoming nuptials, including the name of his intended.

"I'm now 20 years old, so I decided the time was right," he said at Tokyo's Narita airport on his return from the US Masters where he failed to make the cut, the Mainichi Shimbun and other media reported Sunday.

"I got engaged last month, to a junior high school classmate," he said.

Ishikawa and his management are fiercely protective of the youngster's privacy, and despite his status as one of the biggest celebrities in Japan, the media generally plays along.

Japanese sports newspapers have described Ishikawa's fiancee as "a tall, slender beauty with long black hair", a catch-all description that gives little away in racially homogenous Japan.