By Mark Savage, Entertainment reporter, BBC News
Hundreds of U2 fans have queued overnight to meet their rock heroes, who were in London to launch their official biography.
After braving a stormy night on the streets of central London, 100 fans managed to secure tickets for the event, joining 150 competition winners from the band's website.
"My boyfriend came down just after midday yesterday," said Sunny Kang, 26, from London. "I met him at six o'clock in the evening and took over and I've been here ever since.
"It was pretty rainy but there was a good group of us, and I managed to get about half an hour's kip which was more than anyone else got."
U2's appearance was only announced on Thursday, and many of the band's devotees dropped everything to dash to London.
The Irish group were due to arrive at book-sellers Waterstones at midday but, in keeping with time-honoured rock tradition, they kept fans waiting for another hour before making an appearance.
Undeterred, the crowd gave them a loud cheer as they emerged from an elevator surrounded by security guards.