“But she IS the most powerful woman in pop, so if she wants to go unseen, she’ll make it happen.”

An onlooker told the newspaper: “Extras in retro dress were spotted exiting the venue, with festive props including Christmas trees, glitter cannons and tinsel.

“Banana milkshake was used for eggnog, while grape juice stood in for posh champagne.”

The Fate of Ophelia singer is said to have splashed out US$1 million ($1.7m) for the yuletide video, which is said to have a “nostalgic feel”.

They added: “Security was really tight. Taylor and her cast were given numbers instead of names, and were whisked between cars and buildings under a fortress of umbrellas and screens to keep the whole project under wraps.

“You’ve never seen secrecy like it.

“Some shops were informed of filming, but they were told it was for an insurance commercial – something suitably boring that wouldn’t arouse suspicion.

“The budget was massive. Hiring out the shopping centre alone would have cost several hundreds of thousands of pounds.

“Of course, it was decorated and dressed up to look Christmassy. It has a nostalgic feel.”