IKEA has shared instructions for turning its rugs into luxurious fur capes, following revelations that Game of Thrones costume designers used the brand's home accessories to dress their actors.

The spoof instructions – designed for a fake product called Vinter in the simple, line-drawn style characteristic of the company's furniture-assembly manuals – were created by advertising agency SMFB and shared on IKEA's Norwegian Facebook page.

They depict a rug in the shape of IKEA's popular sheepskin Ludde and Skold models, with a three-step process for turning it into a cape suitable for the Westerosi winter.

Step one is to cut the rug where the dotted line indicates to create a hole for the head and neck. Step two directs the wearer to place the rug on their shoulders.

The third step shows the wearer instantly morphed into a bearded swordsman with flowing locks and a thick fur cloak offering protection from falling snowflakes.

The illustration was shared by IKEA last week, after a story circulated that its rugs were being used by costume designers on Game of Thrones, the hit TV series currently in its seventh season.

A key designer from the show, Michele Clapton, made the revelation during a Getty Museum event in Los Angeles last year, but her comments have only now received attention online.

"These capes are actually IKEA rugs," she said in reference to the wardrobe for the Night's Watch, a brotherhood whose members endure the coldest climate in the fantasy land of Westeros. "It's a bit of a trick."

"We cut and we shaved them, and we added strong leather straps and then break them down," she continued. "I want the audience to almost smell the costumes."

The story was reported by publications as diverse as Buzzfeed and Business Insider, and prompted comment from IKEA's UK textile sales leader, Carol McSeveney, that her team was "flattered" to be included in the show. Its Skold and Ludde rugs retail for £40 and £30 respectively.

SMFB creative Pia Ølstad told Dezeen that the agency was inspired to make the graphic because the Game of Thrones anecdote resonated with how the team saw IKEA's brand identity.

"When we saw the articles about how the costume designers at Game of Thrones had rethought and altered the beloved Ludde and Skold rugs, we immediately thought how in line that actually was with IKEA's own way of thinking," Ølstad said. "Through our six-year-long relationship with IKEA Norway, we've learned that there's nothing they love more than when people take IKEA products and make them their own."

"We really wanted to celebrate that. After all, IKEA is all about creating a better everyday life for the many people – even if the Night's Watch aren't who they usually cater to."

IKEA, the Swedish flat-pack furniture giant founded in 1926, has become quick to respond to mentions of it in popular culture. Earlier this year, the company released a spot-the-difference guide after its iconic blue tote bag was copied by fashion house Balenciaga.

Creative agency SMFB is based in Oslo and frequently works with IKEA on Norwegian campaigns.

IKEA ranked first among brands on Dezeen Hot List, a data-based power-ranking of the most influential forces in design and architecture.

Project credits:

Creative team: Linus Hjellström, Pia Ølstad, Alexander Gjersøe, Hans Magne Ekre
Illustrator: Magnus Snickars