Taylor Swift mega-fans have reported suffering from a rather odd health condition after attending The Eras Tour.

Concert goers are experiencing amnesia and have big pockets of the performance that they can’t remember.

Taylor Swift once sang: “Hold on to the memories, they will hold on to you.”

Well, turns out that isn’t exactly true.

Jenna Tocatlian from New York experienced that very phenomenon, telling TIME that ‘post-concert amnesia is real’.

Swift in Texas on The Eras Tour. Credit: NurPhoto SRL / Alamy

Entire plane sings Taylor Swift songs

The 25-year-old Swiftie lucked out when the singer added a ‘surprise song’ to her repertoire for the gig she attended.

Swift sang ‘Better Man’, and Tocatlian would have no idea it even happened if it wasn’t for a quick-thinking pal.

“If I didn’t have the five minute video that my friend kindly took of me jamming to it, I probably would have told everyone that it didn’t happen,” she said.

As she and her friends waited to leave the packed stadium, Tocatlian started listening to Swift’s hit over again on her phone and she began quizzing her mates on what songs the star had played.

She revealed she was asking questions like: “Did she really play that? How much of it did she play?”

The New Yorker reckons it came down to experiencing sensory overload, especially considering Swift hasn’t toured since 2018.

But she isn’t the only one that has experienced amnesia.

Nicole Booz, 32, attended one of Swift’s concerts in Philadelphia.

She revealed to TIME that the show felt like ‘an out-of-body experience’.

Swift in Las Vegas on The Eras Tour. Credit: Imagespace / Alamy

“[It] felt as though it didn’t really happen to me,” she said.

“Yet I know it did, because my bank account took a USD$950 (AUD$1,462, £765) hit to cover the ticket.”

Amnesia such as this isn’t only a Swiftie thing, though, as there is neurological evidence to back up the condition.

Cardiff University neuroscientist Dr Dean Burnett explained to the Daily Mail how and why memory loss like this can occur.

“If you’re at a concert of someone you love, surrounded by thousands of very excited other people, listening to music you’ve got established emotional links to, that’s going to be a lot of emotion happening to you at one time,” he said.

Swift in Florida on The Eras Tour. Credit: Zuma / Alamy

Otterbein University cognitive psychology professor Robert Kraft told TIME that when this happens, it can be both surprising and disappointing for people.

“We paid a lot of money, we’re looking forward to it, and afterwards, we want to luxuriate in our memories of the concert,” he said.

“But our expectations are too high. That’s not what memory is—it’s not a recorder.”

New York State University associate psychology professor Dr Ewan McNay gave a tip for Swifties who want to actually keep their memories of The Eras Tour.

“People could try to jump up and down and scream a little less, to control the excitement,” he said.

So there you have it, Swifties. You need to calm down.