Beyonce Knowles: shy big sister by day, wild girl by night

On the steps of the Mandarin Hotel in Knightsbridge, Beyoncé Knowles is meeting the paparazzi. From the hotel foyer, looking out into the filthy London rain, hair in a functional ponytail, she is a petite silhouette in the flashbulbs. A couple of young male fans are allowed to step forward for a moment with their heroine. Instinctively, the first places his left arm around the singer. No less instinctively, a vast minder detaches the arm from Beyoncé's sleeveless designer dress and puts it back where it came from.

It's an episode that flags up something unusual about Beyoncé's brand of star quality. Fans of, say, Madonna or Cher would never put an arm around their idol and, although she is only 27, Beyoncé has had plenty of opportunities to finesse their brand of starry untouchability. It is three years since she dissolved Destiny's Child after three albums and a run of award-winning hymns to womanly empowerment such as Survivor and Independent Woman; six since her duet with the Brooklyn rap demigod Jay-Z served notice to the world that America's foremost hip-hop star and its emerging queen of R&B were an item.