When you're a die-hard Justin Bieber fan, having a ticket for the concert just isn't enough.

For days, weeks and in some cases more than a month, hundreds of Spanish Beliebers -- fans of the Canadian pop star -- have been camping outside the Madrid venue where he will be performing on November 23.

Their aim: to get as close as possible to their idol when the gates finally open.

"It's tough at night with the cold, but I'm gradually getting used to it," says Andrea Gil, 20, who has come all the way from the Canary Islands, nestled 2,000 kilometres (1,200 miles) away off the African coast.

Wrapped up in a warm, brown coat, a blanket over her legs, surrounded by at least 20 fellow Beliebers, suitcases and bags of food, the graphic design student is part of group number one -- the first to arrive on site on October 14, according to them.

Thirty-four people are part of her group and they take turns in keeping their prized position so that it is never left unstaffed, which under rules tacitly governing the campers would mean it would lose its spot.

There are 13 such groups, all composed of 30 to 40 people taking turns day and night.

Some of them live in Madrid, others in hotels or rented flats, and still others like Gil just camp out, use public baths to wash and charge their phones in a plug in the venue's car park.

A few have tents, others aren't so well prepared, but the prospect of rain doesn't appear to bother them.

From all over Spain, they are united in their love of Bieber, the 22-year-old bad boy superstar singer.

Gil says his songs helped her through difficult times, and the same goes for Cristina Casas, 19, rebel looks complete with nose-ring masking a difficult past.

"I was bullied in school, and I suffered from anorexia for six years," she says.

"I was admitted to hospital weighing 32 kilos, and his music brightened my day. 

"It helped me a lot, it was what made me endure every day, and say it was worth it," she said, singling out "Down to Earth" and "Be Alright" as songs she particularly treasures.

The Beliebers camping out are mostly girls.

But Cesar Ndong is sitting there too, here to look after his younger sister Arsenia Belen, who has come all the way from Murcia in the southeast.

Is he a Belieber too? Not so much... "I'm here for her, because she's a huge fan."