Daniel Radcliffe, Emma Watson and Rupert Grint were greeted by 7,000 screaming fans in outside the cinema in Leicester Square.
They were joined by newcomer Katie Leung, who plays Harry’s first love interest.
The premiere drew an A-list crowd, including Madonna, who turned up with daughter Lourdes, while actress Kate Beckinsale was also there.
Some of the female fans had queued in Leicester Square for over 24 hours to get a glimpse of their hero Daniel, 16, who plays Harry Potter in the film.
He said: “For people to wait out here all day in the pouring rain is just amazing.”