On Wednesday the retailer replaced the "o" and "e" in its logo with two big eyes on the signs of stores including Cardiff city centre.
Earlier this week, in what is thought to be another teaser, a Twitter account called @UnderTheBed2017 tweeted video clips showing a creature’s eyes peeking out from the dark, with the hashtag #UnderTheBed.
This year’s Christmas ad will reportedly feature a "big, cuddly monster". It has been described as a cross between a teddy bear and the Gruffalo, the eponymous character from the children’s book by Julia Donaldson.
Campaign revealed last month that the ad has been directed by Oscar-winning French director Michel Gondry, who is best known for films such as Eternal Sunshine of the Spotless Mind.