Japanese girl band singer in 'child porn' row after magazine picture of her with young boy touching her breasts

Kodansha, the publisher, was planning to run the image in its weekly Manga magazine earlier this month

Tomomi Kasai (fourth from left, back row) is pictured with AKB48 (GETTY IMAGES)

Tokyo police are investigating a Japanese magazine publisher over a photograph of a female pop star in an 'inappropriate pose' with a young boy.

The photograph, which was to be published in the Shukan Young Magazine, shows AKB48 singer Tomomi Kasai, 21, naked with a blond child cupping her breasts.

The image was supposed to be part of a promotion for the singer's debut photo collection called Tomo no koto, suki? (“Do you like Tomo?”), scheduled for release on February 4.

The company announced on January 11 that the issue would be delayed, following concerns over the suitability of the image.

The magazine also offered an apology on its Web site saying: “The photo contains an inappropriate expression.”

Kodansha, the publisher, was planning to run the image in its weekly Manga magazine earlier this month.

Instead, however, detectives were called in after concerns were raised that the picture may infringe Japanese child pornography laws.

The singer, Tomomi Kasai, is a huge star in Japan and has been a performer since the age of 14.

She is known for being a part of the 91-strong girl group AKB48.

The group is one of the highest earning musical acts in the world.

Japan's child pornography laws stipulate that the individuals involved could face a maximum of five years in prison and a fine of five million yen if found guilty.