A year later, the band won the Mercury Prize, making that first album, xx, officially one of the most popular albums in the history of both Britain and Ireland.
Despite the achievements, Romy Madley Croft, the band's vocalist and guitarist, still thinks the band is on a learning curve.
"I think we've grown a lot on stage. When we first started, we were quite reserved and not really very comfortable on stage," Croft said in a phone interview. The band will play at KITEC's Star Hall on Wednesday.
Concert-goers, she says, can expect to hear a good mixture of new tracks - from their new album, Coexist, released last year - and old tracks from the first album.
The band is acclaimed for their ability to bring out mixed feelings through their music, which usually features an upbeat melody but contemplative and sometimes heartbreaking lyrics.
The xx was formed in 2005 in London by Croft, bassist Jamie Smith, drummer Oliver Sim and guitarist Baria Qureshi. When Qureshi left in 2009, the band continued as a trio. Croft remembers that when they started out, they played at local pubs with audiences as small as five people. Another time when they were in Amsterdam, only three people were listening.
At the Manchester International Festival, they played in an intimate, hidden room to 60 people.
But since then, the band's popularity has surged. Becoming headliners at big music festivals such as Glastonbury in Britain has given them more chance to get over their stage fright.
"We've grown a little bit more and are used to playing on bigger stages now, which is something I never thought we would do," Croft says. "I had a lot of fun, sort of playing with it and having the confidence to be on the stage and really perform." She jokes that she used to look at the floor during gigs to avoid eye contact with the audience.
Smith and Croft both sing, which not only gives the band a fresher sound, and "it really helps with my confidence and encourages me because by seeing [him] singing a bit louder and dancing a bit more, it encourages me to push myself a little bit more", says Croft.
In terms of musical style, Croft always struggles to tell people what they are actually doing. But if you press her hard enough, she'll say they make pop music that deals with relationships and emotions. The xx's music is a hybrid of the three members' broad musical tastes, she says.
Sometimes Croft is more fascinated by what people make of their music than they do themselves. "When you're doing interviews and talking to people, they will say: 'You've made a much sadder, slower album.' Other people will say to me: 'You've made a happier, more upbeat one.' I find it really interesting to hear that everyone's interpretation is different."
While many would agree the band's second album contains a more down tempo mood than the first one, "when we made it, I didn't think it was any darker or lighter or anything different from the first album", says Croft, who wrote Angels, the first track on the album, which features her intentionally cold vocal and slow yet emotional bass riffs. The band rarely does this kind of track.
Meanwhile, Croft promises Hong Kong fans that they will hear some of their favourite tracks being played differently live.
"My favourite thing to do is research. It's a bit geeky in that way, but I do that every time when I go to new places."