Taylor Swift fans have hilariously reacted to a mysterious shadowy figure seen watching one of her Madrid concerts from above.

When the 34-year-old pop star played the Estadio Santiago Bernabéu in the Spanish capital, a dark silhouette was spotted near the top of the stadium.

The unidentified spectator was completely alone, in a part of the sprawling auditorium that was apparently blocked off to the general audience.

Swifties flocked to social media to share their tongue-in-cheek theories about the secret identity of the enigmatic concertgoer.

Some joked that it was in fact Kanye West, who has carried on an explosive feud with Taylor for more than a decade.

‘[T]hat was billie eilish who couldn’t afford the ticket,’ vamped one X, formerly Twitter, user, while another quipped that it was Taylor’s ex Joe Alwyn.

‘IM SCARED WTF DELETE,’ exclaimed one Swiftie, while another argued: ‘knowing taylor swift, she’s probably behind this and she’s teasing something’.

‘Aliens watching,’ said one observer, as another wrote: ‘It’s peter pan or peter parker not sure,’ and still another darkly suggested: ‘slenderman.’

One fan sneered that music mogul Scooter Braun, who has fought a years-long legal battle with Taylor over ownership of her masters, is ‘still harassing her i see.’

Quoting a line from Taylor’s new song ‘loml’ — an abbreviation for ‘love of my life’ — from her latest album The Tortured Poets Department, one Swiftie wrote: ‘Dancing phantoms on the terrace.’

Taylor is currently hurtling around the world on her Eras Tour, an economic juggernaut that tipped her over the line into billionaire status.

The Madrid shows took place on Wednesday and Thursday last week at the Estadio Santiago Bernabéu, which is best known as Real Madrid’s home stadium.

From there, she took the show to France, plying the Parc Olympique Lyonnais in Décines-Charpieu on the outskirts of Lyon.

Her next stop is the Murrayfield Stadium in Edinburgh, the largest stadium in Scotland, where she will perform this Friday, Saturday and Sunday.

At a number of recent shows, Taylor has been supported by her dashing NFL boyfriend Travis Kelce, whom she has also watched at several of his games.

Between stops on the European leg of her tour, Taylor and Travis enjoyed a luxurious five-day getaway to Lake Como, where they were spotted cruising on the water and dining at their €20,000 a night villa at the five star Grand Hotel Tremezzo.

Travis recently shared how he remains levelheaded as he and Taylor conduct their whirlwind romance under the glare of worldwide scrutiny.

‘When you have good family and friends around you, it makes that aspect of life that much easier,’ said Travis, whose brother Jason Kelce is also an NFL star.

‘I’ve always been a very grounded guy, you know,’ he maintained on Good Morning America. ‘It might not come off like that when I’m playing football. But off the field, I just wanna be a genuine person. I try not to get too far down the road, because you just never know what opportunities are gonna present themselves.’