Fans flocked to London's Wembley Stadium on Thursday ahead of Taylor Swift's return to the stage a week after her Vienna concerts were cancelled due to a foiled suicide attack plot.

Hundreds of ecstatic so-called "Swifties" streamed towards the stadium hours before the American mega-star was due to wrap up the European leg of her "Eras" tour with the first of five sell-out shows.

"It doesn't feel real, that it's actually happening!" excited ticket-holder Katie Moulson, 24, told AFP as she arrived at Wembley mid-afternoon.

Around 90,000 fans will again pack London's Wembley Stadium for the first date in the five-day run, with additional ticket checks and restrictions in place.

Last week, all three of the American mega-star's shows in the Austrian capital were cancelled following the discovery of a Daesh-inspired plan to launch an attack using explosives and knives.

Three alleged Daesh sympathisers have been arrested on charges of plotting the atrocity, which was thwarted with the help of US intelligence.

London's Metropolitan Police have said there was "nothing to indicate that the matters being investigated by the Austrian authorities will have an impact on upcoming events here in London."

Fans of Taylor Swift pose for a photo outside Wembley Stadium. AFP

The force was working "closely with venue security teams and other partners to ensure there are appropriate security and policing plans in place," a police spokesperson said in a statement.

Fans have been warned on Wembley's website to expect "additional ticket checks" around the stadium.

'Tay-gating'

Swift's return to the British capital, following three sold-out shows in June, also comes two weeks after three young girls were killed in a stabbing at a dance class themed around the pop star's music in northwest England.

Following the knife attack, Swift said she was "completely in shock" and at a "complete loss for how to ever convey my sympathies to these families."

She has not yet commented on the decision to cancel the Vienna shows.

 Fans of Taylor Swift pose for a selfie photograph next to a mural of the performer outside Wembley Stadium. AFP

London's mayor Sadiq Khan told Sky News that the city was "going to carry on working closely with police, ensuring that the Taylor Swift concerts can take place in London safely."

"We have a huge amount of experience in policing these events, we're never complacent, many lessons were learned after the awful Manchester Arena attack," Khan added.

Fans without tickets will also not be allowed to "tay-gate" the event — the practice of Swift fans standing outside the venue during the live show to hear the music.

Royal audience

The stadium's website says that "no one is allowed to stand outside any entrance or ... at the front of the stadium" and "non-ticket holders will be moved on."

While the practice was not permitted at her June concerts there, some fans still managed to gather outside Wembley.

After two performances in Madrid at the end of July, Swift noted around 50,000 "people came out and listened to the show" from a nearby hillside on both nights, "participating in the show from afar."

Meanwhile, her last London appearances were attended by some high-profile names.

They included Keir Starmer, who was then running to become Britain's prime minister, and Prince William — celebrating his birthday —along with his children, Prince George and Princess Charlotte.

The singer posted a photo posing with the royals and her boyfriend, American football player Travis Kelce, with the caption "Happy Bday M8! London shows are off to a splendid start."

After wrapping up the European leg of her record-breaking tour — which began in Paris in May and saw the star perform across the continent — Swift will then head back to North America. Its final leg there starts on October 18 in Miami.

Agence France-Presse