"We had to change our hairstyles, we had to have bigger hair. At one point we even had proper beards. Some of it still remains."

Always ones to pay attention to detail, Royksopp have got this reinvention thing sorted.

Such is their desire to move and evolve, they have made significant changes to their work - as well as their hair.

Their latest album, The Understanding - which was released in the summer - has taken their progression from studio producers to live act one step further. They now fancy themselves as "21st-Century electronic singer-songwriters".

"We needed to do something different," explains Svein Berge, one half of the Norweigan dance duo. "Something that was new to us, hence the lyrical approach."

It also seems the beards play a bigger part than we might imagine. "It's part of the process you go through: The longer the hair and the beard, the more beaujolais you drink. It's stage three of the seven stages of songwriting."

The Understanding lurches from the delicate to the haunting to the boisterous. Apart from a few tell-tale signs, it doesn't sound like Royksopp at all.

It would have been easy for these electro-eccentrics to give us more of the same, following the success of their debut, Melody AM.

Just look at the riches that unfolded in the wake of its release in October, 2001: 1,000,000 copies sold worldwide, 500,000 of them in the UK alone; tours with Basement Jaxx and Moby, headline tours of their own culminating in two nights at London's Somerset House and an appearance at Glastonbury; a Brit nomination for Best International Group; an MTV Europe award for best video and remixes for A-list artists as disparate as The Streets, Coldplay and Felix Da Housecat.

But a Melody AM part deux was never on the agenda.

"Our mindset has always been to do our own thing," says Svein.

"Who was supposed to add pressure? The record-buying public? I don't think so. The critics? We're not afraid of them."

The experiement worked. The Understanding sold more than 80,000 copies in the first month of its release.

The singles Only This Moment and 49 Per Cent set the tone for a varied reportoire of surreal humour, energetic electro, high-octane rushes and haunting, mellow sounds.

Following a rapturouslyreceived performance at the Isle of Wight's Bestival, Svein and Torbjorn Brundtland are now on a full UK tour, their first in two years.

The duo are quietly riotous on stage, given to pumping their hands in the air and shaking their new haircuts. They're a well-oiled machine and they rock out.

Expect dreamy swirls and vocodered vocals but also storming, sub-bass heavy anthems. It's likely they will also play a few numbers from Melody AM - both albums share an equal place in the pair's heart.

"It's like trying to compare two testicles," says Svein.

"One is not better than the other. Both are vital to the Royksopp anatomy."

Starts at 9.30pm, tickets cost £15. Call 01273 709709.