Bieber fever raged from the west end of London to the east Monday, as teen star Justin Bieber switched on the Christmas lights at the city's two biggest shopping malls.

Thousands of young and mostly female fans waited hours for the 17-year-old singer to appear, first at the Westfield shopping center in west London, then hours later at the new Westfield Stratford City mall near the 2012 Olympic Park in the east.

Bieber traveled the 12 miles (18 kilometers) between the malls by helicopter.

The star, who won two prizes at Sunday's MTV Europe Music Awards in Belfast, told fans that his favorite thing about London was "all the girls."

The singer has strongly denied allegations by a San Diego woman that he fathered her 3-month-old child during a brief liaison.

He appeared to refer to the claims at Sunday's MTV awards, when he praised his fans for staying with him despite "a lot of crap on the Internet."

The singer, dressed in a gray woolen hat and black leather jacket, said backstage Monday that despite the ups and downs, he was grateful for his fans.

"I take it with a grain of salt _ it's been incredible, my fans are amazing and I wouldn't have it any other way," he said.