A Japanese starlet has shaved her head and issued a tearful YouTube apology after spending the night with a man, scrambling to redeem the girl-next-door image of all-female group AKB48. Pictures of the roughly-shorn head of Minami Minegishi, 20, were emblazoned on national newspapers yesterday amid news that the pop princess had broken the band's cardinal rule: no dating. A sobbing Minegishi told fans she had decided to shave her head as an act of contrition after a popular weekly magazine published claims she spent the night with a 19-year-old boy band member. "I don't believe just doing this means I can be forgiven for what I did, but the first thing I thought was that I don't want to quit AKB48," she says in the video, which had been viewed on YouTube more than three million times. Minegishi, who had long, silky hair at the time, was snapped leaving the apartment of Alan Shirahama, a dancer in an off-shoot of the popular boy band Exile. Tabloid magazine Shukan Bunshun published its article on Thursday, and hours later Minegishi was pleading to be allowed to remain with AKB48, one of the world's most successful acts by revenue. The tryst was "thoughtless and immature", she told fans. "If it is possible, I wish from the bottom of my heart to stay in the band. Everything I did is entirely my fault, I am so sorry." AKB48, a 90-strong pool of girls in their teens and early 20s, is a money-printing juggernaut that makes much of the accessibility - and the implied availability - of its idols. Fans have frequent opportunities to meet their favourites, who are rotated in and out of the public eye, according to their popularity. In return for fame, members of the collective must adhere to strict rules of behaviour. They are allowed to have "one-sided romantic feelings" for a boy, but can never progress beyond hinting at their crush. Moreover, they must never disabuse their legions of male fans that they might one day stand a chance with their fantasy woman.