“BRUISES? You can’t imagine!” declares Icelandic actor Bjorn Thors. “I feel like I have been run over by a train – twice.”

Thors was at the Lyric Hammersmith, where he has been appearing in Metamorphosis, a stage version of Franz Kafka’s peculiar novella.

That’s the one in which the leading character Gregor wakes up one morning to discover that he has turned into a giant insect.

Thors is playing Gregor, in what one critic called “one of the most extraordinary physical performances in London”.

The production has now taken to the road and appears at the Liverpool Playhouse for a week from next Tuesday.

The production is a joint collaboration between the Icelandic theatre group Vesturport and the Lyric Hammersmith. Some of the cast are Icelandic, some British.

And there are two directors, David Farr, artistic director at the Lyric Hammersmith, and Gisli Orn Gardarrsson, of Vesturport Theatre.

“They have their own dialogue between themselves and while they are both very different directors in the way they approach the work, it has been a successful collaboration,” explains Thors.

Vesturport is known for its unusual approach to the theatre. They staged Romeo and Juliet in the air, Woyzeck on water, and now Metamorphosis is played out on the walls.

“It is highly physical and very different from your normal theatre,” says Thors, an actor who worked in theatres across Europe but is making his British debut.

“There’s a lot of climbing around the set for 90 minutes.” And trampolines. The set, from Borkur Jonsson, has rooms on two different levels, the upstairs room upside down so we can see Gregor the beetle climbing on the walls and ceiling.

But don’t expect to see a bug-eyed monster. Thors is attired in grey suit, white shirt and tie, no six legs, no antennae. “The thing is that everyone has some image of the scariest bug they have ever seen so we leave that up to the audience.”

Nevertheless, he has to act like an insect, which does involve all that crawling about on the walls.

The play follows the original story to some extent, says Thors. It has also been jointly adapted by Farr and Gardarsson. “It is the same story but the writers have taken their own liberties. They have their own style and way of telling the story.”

Kafka’s tale never explains why someone would wake up as an insect, and concentrates instead of people’s reactions to his predicament. It’s not good, as the family either ignore him or fail to feed him and even a faithful sister turns against him.

In the event, the rejected Gregor dies a miserable death. “It’s quite a dramatic death scene, actually,” he says. “As dramatic as these sorts of scenes can get and I think it is one of the most powerful moments in the play.”

For most theatregoers, it will be a first chance to see a production from an Icelandic company. “There is a strong theatre scene in the country but not a lot of touring outside,” he says.

Vesturport has, however, established an international reputation since its creation in 2001 and has toured, most notably to London.

“It is made up of a group of young actors and artists, many of whom, like myself, went to the same arts university in Iceland,” says Thors. “We have a common interest in creative art productions, doing theatre and films but our most successful things have been the physical theatres shows.

“It is different from other companies in Iceland, I guess, as the physical side of the performance makes it pretty unusual.

“They always provide a fascinating trip to the theatre and you see something different. They have this raw energy approach to the work.”

It is his first time with the company and his first working job in Britain, having visited London only a couple of times. “I am looking much forward to seeing the other side away from the capital city,” he says.

* METAMORPHOSIS opens at the Liverpool Playhouse on Tuesday, and runs until February 9.