Onesie is the item predicted by supermarkets and high street stores alike to be the number one Christmas gift for 2012.

Celebrities were early adopters of the trend, with the likes of Rihanna, Robbie Williams, Tulisa, One Direction and Tom Daley all stepping out in their own versions of the adult romper suits.

Holly Willoughby appeared on This Morning wearing one, Keith Lemon stepped out in Asda’s Incredible Hulk onesie and Amy Childs vajazzled a £60 ($90) velour all-in-one, 2,000 of which sold out on her website in two days.

And now, as Christmas approaches, it is clear that the people of Britain have embraced the all-in-one too.

Evidently millions have already bought one for themselves. George at Asda, who are predicting that onesies will be the number one Christmas gift this year – say that sales of onesies have soared by a staggering 606% on year, and the word “onesie” now the most searched-for term on their website.

Marks & Spencer and Debenhams have reported staggering sales results too, with M&S saying last month they would be producing an additional 10 styles of the onesie in time for Christmas, and Debenhams reporting a 155% rise in sales in October than the previous month.

A spokesman said at the time they’d sold 2,075 units in just one week – and that was just the tip of the iceberg.

Onesie is the item predicted by supermarkets and high street stores alike to be the number one Christmas gift for 2012

With Christmas now fast approaching, many more are expected to jump on the onesie bandwagon.

A poll on the George at Asda Facebook page revealed that 42% of customers are planning to buy a onesie as a gift this year, and a third admitting the ultra-forgiving onesie will be their outfit for Christmas day.

As a result, Asda say they have stockpiled one million onesies to meet demand, and have launched an online Onesie Shop for customers. There, shoppers can buy Sponge Bob Square pants onesies, onesies in tiger print and dalmation, a Fair Isle onesie inspired by the Burberry catwalk show – and thatIncredible Hulk onesie as worn by Keith Lemon, which sales analysts at the store predict will sell out in 24 hours (no fighting in the aisles over the last one now please).

Fiona Lambert, George Brand Director said she predicted sales of onesies will go on soaring right up until the big day.

“Onesies are the must-have item for Christmas 2012,” she said.

“Each week at George we see sales soar higher than the week before which we are attributing to celebrity influence.

“Due to such high customer demand we have ordered in thousands of extra onesies and launched our dedicated online <<Onesie Stop Shop>> to ensure our shoppers don’t miss out on the perfect outfit for a cozy Christmas morning, day and night for the whole family.”