Gotye: All hail the new wizard from Oz

Gotye's single has shot to No 1, having had more than 70 million hits online. It's a reward for years of obsessive work, he tells Elisa Bray

"I was having a good time yesterday going, 'I've got a No 1 single and no one in London has recognised me in two days.' I'm loving it!" says Gotye. The Belgian-Australian electro-pop artist would be wise to make the most of this anonymity in the UK – it surely won't last for long.

Gotye (pronounced "Gaultier", like the fashion designer), born Wouter de Backer in Belgium, and known as Wally, is already a chart-topping star in Australia, where he moved with family at the age of two. It's all thanks to his hit single "Somebody That I Used to Know" which has won him three Aria awards (the equivalent of our Brits) and, as of Sunday, become a UK No 1. His new album, Making Mirrors, looks set to follow, lying at No 4 in the midweek charts. Everyone's been talking about "Somebody That You Used To Know" because it has racked up more than 71 million views on YouTube. In fact, as Backer points out, if you include all the other websites that have hosted the video, its total plays surpass a mind-blowing 120 million.

It's not hard to see why it has resonated with so many people; beginning with a quirky xylophone riff, the lo-fi song has the most insistent melody, while the story of a couple's break-up is portrayed ingeniously. Filmed close-up, Backer stands naked singing his angst ("No you didn't have to stoop so low/ Have your friends collect your records and then change your number"), as his body is covered by paint, camouflaging him with the wall. When rising singer Kimbra Johnson unexpectedly joins in to provide a counter-argument, it feels as though we're being let into an intimate confrontation.

We meet at Wilton's Music Hall in east London, before his gig, which sold out in just 20 minutes. Backer, 31, is instantly recognisable as the skinny, tousle-haired singer from the video, albeit with clothes on. Today he's dressed in true Aussie casual style.

"I'm not really into the personality aspect of pop star, so I would quite happily have No 1 singles and no-one ever recognise me again", he says, with the air of a bedroom-producer.

The Melbourne musician is a self-confessed music obsessive, a maverick whose complex, experimental songs on the new album range wildly from lo-fi pop to electro-dub and Motown. Before he stormed the charts, he was a leftfield artist whose success extended to winning iTunes Album of the Year in 2008 for his second album, Like Drawing Blood, crafted by sampling old records. "I like finding things I have no idea about, that are by artists I never knew existed," he explains. "A silly album-cover that is just too peculiar to leave sitting in a box – I have to get it just to see whether it might also reveal some musical spark. It's partly the junkyard explorer's desire to find something, and sometimes that leads to the discovery of breaks and beats and sounds."

A constant search for interesting samples means that he and his band-members are always out record shopping. He grins. "We always end up with 50kg each of records each on the road."

He praises fellow Antipodeans The Avalanches for their 2000-released "amazing thrift-shop record" Since I Left You, which masterfully wove in old hip-hop and funk records, as well as DJ Shadow and Cut Chemist as influences on his sampling technique.

Backer is quite happy not belonging to any scene. The artist he cites the most as inspiration is another musical maverick. Kate Bush crops up no less than four times during our conversation. "I guess when you're part of these burgeoning scenes there's the excitement of being part of this wave, but I see that as really different to what someone like Kate Bush, who I really admire, does, which is crafting your own sound-world over a long period of time.."

For Making Mirrors, he set himself a new challenge: not to rely on others for hooks by sampling records, instead turning to instrumentation. So fascinated is he by unusual sounds that rarities such as the chromaharp and the aboriginal Winton Musical Fence are employed in the songs. Garage sales, thrift shops, antiques markets, second-hand music shops – that is where he'll unearth his treasure: an obscure vintage instrument, or an old record containing the obscure chord that will inspire a whole song.

"I wanted to set myself a new method of working. I was like, 'what if I can take it a step further and make more sounds from scratch', so that set me off just trying to discover interesting instruments, like weird old snare drums, audio harps and thumb pianos."

Still, the mixing proved a challenge too far for the entire album; his own ambition was pushing him to the point of wanting to give it all up. "Getting mixes right took me to the edge of going, 'I'm not good enough, I've got to quit, I'm never going to finish this album'. I got through some fairly depressed places. The height of what I'd aspired to was bringing me undone, affecting all my thoughts every day. It was obsessive at times, but I got through it."

For Making Mirrors, instead of recording in cramped rooms at shared houses around Melbourne, he decamped to a barn on his parents' five-hectare estate in Victoria where he could set up a permanent studio with the equipment he'd amassed. It posed more practical issues than he'd perhaps expected. "Birds would land on the roof and ruin vocal takes. And actually it's near the road that leads to the beach and people drive at about 100kph, so listening back a bit later after I'd gone home I would hear, just between a take, vroom!"

If Backer is meticulous now about his music, he has been the same since his teens. In his first high-school band, a grunge act he started with Lucas, the bassist in his current touring band, his musical obsessiveness became clear when they graduated from covers of Alice in Chains and Nirvana to his self-penned creations. "I was such a Depeche Mode obsessive. I was copying their production aesthetic and Martin Gore's songwriting, so I was writing these synth-pop/rock songs.. I remember all our friends would be in punk bands going into the studio bashing out eight tracks as a demo, and I would go in there and say, 'I've got this one song and it's got these layers of synthesisers and I want to use electronic drums' and the local engineer would say 'whoah!'. We managed to record seven songs in almost as many years."

The hit that has made him a star almost didn't reach fruition. After writing the female perspective, he had to track down the perfect vocalist. "That's when I thought, 'maybe this isn't going to happen'. I had one person cancel on me who I thought was perfect – it was almost the final straw. It felt like the track wasn't meant to be."

"Somebody That I Used to Know" wasn't inspired by a recent break-up. Backer is in a stable five-year relationship. "My girlfriend and I were talking about whether happiness domestically is actually a real barrier to doing anything creative. Does that mean we create drama? That seems silly, but maybe it pushes you to looking further."

'Making Mirrors' is out on Island. Gotye plays Shepherd's Bush Empire in London on 29 February