The Japanese pop star, Mayu Tomita, has been stabbed more than 20 times in Tokyo.

The 20-year-old singer was allegedly attacked by an obsessed fan, who stalked her before a performance she was due to give. She is currently in critical condition after repeated stabbings to her neck and chest.

The 27-year-old attacker was arrested at the scene. Police believe his dangerous obsession grew from an apparent slight he perceived, when the pop star had returned a gift her had sent her. He tweeted that she was 'looking down upon him'.

Mayu Tomita rose to fame in Japan after appearing on an online series Secret Girls, about a group of five schoolgirls who lead secret lives as J-Pop stars.