Robert Pattinson described the Twilight craze as a "virus" as he attended the UK fan party of the franchise's second film.
The British actor joined co-stars Kristen Stewart and Taylor Lautner at the event for New Moon in London's Battersea Park to the sound of thousands of screaming fans.
Many of the fans had been queuing to get into the venue since early on Thursday morning - and the trio insisted they were surprised at the response.
After signing autographs and posing for pictures with fans, Robert - who stars in the films as vampire Edward Cullen - said: "We went to Japan earlier on in the year. There wasn't that much of a reaction - but last week when we went again, it suddenly exploded, the same as here," Robert explained.
"I don't know how, it just explodes so quickly. It takes seven months to take hold - it's like a virus."
Taylor, who was also greeted by howls in reference to his character Jacob Black morphing into a werewolf, said he was surprised by the fans' reaction in the capital.
He said: "I'm stunned - I knew it was going to be good, but this is amazing. The fans in London are surprising me... it's amazing to know we have this support behind us. It makes us feel like we're at home."
Kristen, who plays high school student Bella Swan in the film, said: "It's really exciting. I used to not know what to do with myself, but now I can actually enjoy it."
New Moon is released in UK cinemas on November 20.
© Press Association