Asda is finally letting the media into its headquarters - albeit in the form of an imaginary CGI Christmas world.

Launching on Sunday, the retailer’s ‘Best. Christmas. Ever.’ campaign features a young girl and her grandfather, who secretly sneak into Asda’s Christmas headquarters, known as the Imaginarium, where they discover the secrets behind the supermarket’s seasonal ranges and products.

The 60-second slot, set to the tune of Fleetwood Mac’s Don’t Stop, is somewhat ironic given outgoing boss Sean Clarke imposed a media lockdown at its real-life Leeds HQ.

Asda is hoping it will be a case of ‘yesterday’s gone’ after a tough two years in which it has struggled for sales.

With a Christmas boost more crucial than ever, the ad, created by Saatchi & Saatchi London, launches simultaneously across ITV, Channel 4 and Channel 5 this weekend to show the supermarket’s Christmas ranges are designed to match “Asda shoppers’ unstoppable enthusiasm for life”.

“From the uplifting song choice down to the whimsical world the ad invites the viewer into, Asda shows shoppers they don’t need to compromise on providing the most magical experience for their loved ones: from the big items to the little extras, Asda caters for all of their Christmas needs, at a price they can afford,” said a spokesman.

Featuring reindeer powering a giant food mixer to make Christmas puddings, canapés and mince pies being assembled by tiny Asda Imaginarium workers, and Christmas Smash Igloo cakes being tested by strapping weightlifters, the ad aims to show Asda’s “creativity, innovation and quality”.

Four further 30-second ads will be rolled out over the festive period, which will focus on key festive shopping moments: gifting, home decorations, parties and ‘the Big Shop’.

In a first for the retailer, Asda will also engage dynamic technology to create tailored TrueView videos, with YouTube Christmas bumpers, short-form two-second content and carousel ads on Facebook.

The campaign will also feature a gamified Snapchat filter, in which people can become the striped weightlifters from the ad.

Asda chief marketing officer Andy Murray said: “Earlier in the year we held sessions with our customers to get feedback on our Christmas range. As we talked to them about Christmas we could see how much joy and happiness planning their Christmas brought them - we knew we wanted to reflect that in our ad. When we saw their reactions to our food - the way it surprised them and made them smile - as well as the incredible pride and attention to detail our product developers had put into creating it, the inspiration for the Imaginarium was born.”

Eilidh Macaskill, Asda’s vice president creative and media, added: “By combining CGI animation and some spectacular real-life venues, the ad and the wider campaign is a love letter to our customers and products.”