It’s become one of the biggest moments of the year in the retail calendar, and everything surrounding the £7million campaign is a closely guarded secret.
So there will be red faces at John Lewis today after bungling staff put cuddly toys of the main character Moz on sale at one of its store three days early.
The grey cuddly monsters wearing one white sock were available for £20 next to the checkout area at the shop in Canary Wharf, East London, on Tuesday.
But they were taken off display after a shopper spotted the error. It blows open the subject of the advert, which John Lewis was trying to keep secret until tomorrow.
The City worker who spotted the error told The Sun: ‘I’ve seen the #underthebed hashtag and trailers. I thought it had to be character from the adverts.
‘When I went in to the same shop later the monsters had been completely removed from sale. I had a little chuckle to myself because I realised someone must have made a big mistake.’
But a John Lewis spokesman told MailOnline today: ‘We’re not commenting on this.’
The error comes after John Lewis tweeted a teaser video on Monday showing a creature with large eyes accompanied by the hashtag #underthebed.
John Lewis tweeted a teaser on Monday showing a creature with the hashtag #underthebed
It has been posted three times this week on the account @UnderTheBed2017, which was created last month, and has since been retweeted hundreds of times.
Many have speculated that it is the trailer for this year’s John Lewis Christmas advert, commenting that it features the same font used by the retailer.
John Lewis has also been trying to tease its advert to the public by transforming the ‘o’ letters in its name into two eyes on store fronts.
Last year’s commercial, which featured Buster the Boxer, was an instant hit with viewers. The advert told the story of a little girl called Bridget who loves to jump.
Her mother and father buy her a trampoline, toiling while she sleeps to build it before hiding it in the garden to surprise her with on Christmas Day.
The retail giant has also been trying to tease its advert to the public by transforming the ‘o’ letters in its name into two eyes on store fronts (Oxford Street store in London is pictured)
As the snow falls, set to a cover version of ‘One Day I’ll Fly Away’, an array of animals start using it as the Boxer watches forlornly through the window.
The next morning Bridget sprints out to use it for the first time but her joy turns to shock as cheeky Buster has the last laugh and uses her new toy before her.
Paula Nickolds, who took over as John Lewis managing director in January, is seeking to revive the 152-year-old chain in the face of fierce competition online.
The 44-year-old is under pressure to deliver a bumper Christmas this year, which will be her first official festive season since taking control of the firm.
John Lewis expects its gin advent calendar and coding and intelligent led toys like Lego Boost to be bestsellers at Christmas, which is behind 40 per cent of its profits.