THOUSANDS of "tween" girls jammed a vast square and screamed in unison throughout teen superstar Justin Bieber's free concert, which drew 200,000 people to Mexico City.
Bieber opened with his hit song Baby, while his adoring fans filling the city's main plaza sang along or shouted "Justin! Justin! Justin!"
"Mexico City, there is a lot of people today!" Bieber told the crowd. "Every one of you is my biggest fan."
Dressed in white jeans and a gray sweatshirt that he took off to reveal a white T-shirt, the singer wore neon yellow tennis shoes and was accompanied by five dancers in neon colours. Four giant screens showed parts of his music videos to the crowd of mainly girls and their parents.
The crowd went wild when Bieber asked a fan onto the stage, gave her a bouquet of flowers and sang One Less Lonely Girl into her ear. The girl didn't stop crying.
The plaza was covered in a sea of purple as the mainly 10- to 14-year-old crowd paid homage to Bieber's favourite colour.
After singing a couple of songs while playing an acoustic guitar, Bieber changed into an all-black outfit and sang some of his more energetic songs, including Somebody To Love.
At a news conference before the concert, the teen star said there is no artist he would spend days in line waiting for.
"There is no one I admire so much to do something crazy, but if Michael Jackson were here, I would do it for him. So, I do understand the emotion that the girls feel and that makes me feel very honoured," Bieber said.