The lads have been enjoying some time off in Barcelona, Spain as they continue their trek around Europe on their Take Me Home tour.

Styles was pictured topless and taking in the sun as he put performing to the back of his mind.

Other photos of fans with the singer topless have also since appeared on Twitter.

Styles shows off his admirable tattoo collection in the snaps, with much of the upper half of his body plastered in ink.

One Direction meanwhile due are to play the Pavelló Olimpic venue in Barcelona tonight (May 22).

The 19-year-old singer's life turned upside down in 2010 when he was placed in the boyband on the UK X Factor, with global stardom soon ensuing.

The lads recently announced a worldwide 2014 stadium tour, but speaking to the Irish Herald, father Bobby Horan said that his son hasn't changed a bit despite all the fame. He said:

"The good thing is that he's still the same young fella that left our house in Mullingar that day in 2010."

One Direction are due to play in Horan's homeland Ireland on the 2014 Where We Are tour with a show at Dublin's Croke Park next summer.

Bobby Horan added that he thinks his son will be taken aback when he plays the venue. The proud dad said:

"The only time Niall was in Croke Park was when he auditioned for the X Factor in 2010, but that was in one of the conference rooms. He wasn't on the pitch or in the stands, so I know he's going to be amazed at the size of Croke Park."

The news was announced earlier today (May 21) and the official book will be titled, 'One Direction: Where We Are: Our Band, Our Story'. While it isn't due to be released for several months, pre-order has begun for around $15 (£10) on Amazon.

The message on the 'Little Things' heartthrobs' newsletter explains: "Calling all One Direction fans! This is the only official book from 1D charting their journey over the last year and a half—from the places they've visited and fans they've met, to their thoughts and feelings, hopes and dreams, highs and lows. It has been a phenomenal year—and this is a phenomenal story."

The publication, for which the cover photo can be seen below, also promises to include "exclusive beautiful photos, backstage snapshots, hand-written annotations and brand new insights into the boys’ world."

Watch One Direction answer fans' questions during a recent concert here:

The British group performed at the Mediolanum Arena to a packed crowd as they continue their Take Me Home European tour.

Speaking on Twitter post-gig, Niall Horan said that their fans had been particularly enthusiastic all day - meaning that come stage-time, the crowd was hyped. He said:

"Milano was epic! U guys were crazy!"

The Irishman later added: "Absolutely mental in Milan last night! Knew it was gona be! I could tell by the rampage of our fans in the streets in the daytime."

Next up on One Direction's touring schedule is a show in Barcelona on Wednesday night (May 22).

The lads have been enjoying some time off in Barcelona, Spain as they continue their trek around Europe on their Take Me Home tour.

Styles was pictured topless and taking in the sun as he put performing to the back of his mind.

Other photos of fans with the singer topless have also since appeared on Twitter.

Styles shows off his admirable tattoo collection in the snaps, with much of the upper half of his body plastered in ink.

One Direction meanwhile due are to play the Pavelló Olimpic venue in Barcelona tonight (May 22).

The 19-year-old singer's life turned upside down in 2010 when he was placed in the boyband on the UK X Factor, with global stardom soon ensuing.

The lads recently announced a worldwide 2014 stadium tour, but speaking to the Irish Herald, father Bobby Horan said that his son hasn't changed a bit despite all the fame. He said:

"The good thing is that he's still the same young fella that left our house in Mullingar that day in 2010."

One Direction are due to play in Horan's homeland Ireland on the 2014 Where We Are tour with a show at Dublin's Croke Park next summer.

Bobby Horan added that he thinks his son will be taken aback when he plays the venue. The proud dad said:

"The only time Niall was in Croke Park was when he auditioned for the X Factor in 2010, but that was in one of the conference rooms. He wasn't on the pitch or in the stands, so I know he's going to be amazed at the size of Croke Park."

The news was announced earlier today (May 21) and the official book will be titled, 'One Direction: Where We Are: Our Band, Our Story'. While it isn't due to be released for several months, pre-order has begun for around $15 (£10) on Amazon.

The message on the 'Little Things' heartthrobs' newsletter explains: "Calling all One Direction fans! This is the only official book from 1D charting their journey over the last year and a half—from the places they've visited and fans they've met, to their thoughts and feelings, hopes and dreams, highs and lows. It has been a phenomenal year—and this is a phenomenal story."

The publication, for which the cover photo can be seen below, also promises to include "exclusive beautiful photos, backstage snapshots, hand-written annotations and brand new insights into the boys’ world."

Watch One Direction answer fans' questions during a recent concert here:

The British group performed at the Mediolanum Arena to a packed crowd as they continue their Take Me Home European tour.

Speaking on Twitter post-gig, Niall Horan said that their fans had been particularly enthusiastic all day - meaning that come stage-time, the crowd was hyped. He said:

"Milano was epic! U guys were crazy!"

The Irishman later added: "Absolutely mental in Milan last night! Knew it was gona be! I could tell by the rampage of our fans in the streets in the daytime."

Next up on One Direction's touring schedule is a show in Barcelona on Wednesday night (May 22).

Member Howie Dorough told MTV News that to see a new group paying homage to an act as established as themselves was great as it's important to acknowledge music's history:

"I think they did a good job on it. One of the writers, that's written almost all their big stuff, Rami Yacoub, he worked with us in the early days with Max Martin and stuff like that, some of the biggest songs of ours. The sound that they've originated was definitely not too far from where it came, from the same Swedish camp."

"It's nice to see groups like that pay homage to us. We definitely paid homage to groups in the earlier days that we admired like Boyz II Men, Color Me Badd, Shai, New Edition." Dorough added: "So it's cool. I think they did a great job. It seemed like it went over really well."

ABC's three-hour telecast of the event averaged 9.47 million viewers and earned a 3.6 rating/10 share among the key 18-49 age group.

The show aired live from Las Vegas and had a fair amount of drama, from Justin Bieber getting booed while making an acceptance speech to singer Miguel trying to jump between stage platforms and landing awkwardly on an audience member's neck.

Other unusual highlights included 'Bawitdaba' star Kid Rock slamming some of the event's performers' artistic integrity on stage, telling the crowd and viewers alike: "Let's give it up to people lip-synching under pre-recorded music!'

Songstress Taylor Swift walked away with an astounding 8 prizes, while UK boyband One Direction were presented with 3 titles ( Top New Artist, Top Pop Artist and Top Duo/Group).

Watch clips from the Billboard Music Awards below:

Speaking to Seventeen magazine, the 'Wings' ladies explained that because the lads have enjoyed such amazing success in America they wanted to know how to approach trying to launch their career there so asked for some words of encouragement:

"I asked the boys from One Direction how to make it in America and they basically said, 'Be yourself and you can't go wrong'. People know when you're trying to be someone you're not."

Singer Leigh-Anne Pinnock added: "Just be true to who you are. So that's what we've been doing!"

Meanwhile, Little Mix took to their official Twitter page earlier today (May 20) and told their American fans that Amazon is streaming their debut album now so that they can listen to it in full: "US Fans! Wanna listen to DNA before it comes out? @Amazon is streaming the FULL album."

Watch Little Mix perform 'Going Nowhere' live during an MTV session here:

The band won the Top Group, Top New Artist and Top Pop Artist awards at the ceremony in Las Vegas last night (May 19).

The news seems to have sat well with Niall Horan, who gushed on Twitter today (May 20):

"Wow ! Wake up and find out that we've won 3 billboard awards! Can't believe it! Thank you so much best fans ever ! Love you soo much xxxxxxx."

He continued: "Top group, top new artist, top pop artist! You guys are the best! Thanks very much! Means so much!"

Other winners on the night included Taylor Swift, who bagged eight awards, and Justin Bieber, who won three.

The former meanwhile made headlines after being seen sticking her tongue out at an embrace between the Canadian and former girlfriend Selena Gomez.