The singer surprised fans when they noticed a peculiar detail at the Eras Tour in Stockholm.

Fans of Taylor Swift were stunned when they noticed a small detail about the singer’s appearance during one of her Eras Tour stops in Stockholm, Sweden, as the star had a peculiar mark on the side of her neck.

A Swiftie shared a clip of Swift singing at her piano on stage, zooming into the right side of her neck, which had a noticeable red mark. The fan set the clip to Swift’s song “So High School,” with text over the video reading, “Someone’s feeling ‘So High School’ with a hickey,” hypothesizing that the mark might’ve been given to her by her boyfriend, Travis Kelce, who was in Europe with the star recently.

Other fans thought the same thing upon seeing the video, with a top-liked comment saying, “Flat iron burn or hickey and in her idgaf era?”

Many Swifties were shocked at the clip, with replies like, “WHEN I SAY I DROPPED MY PHONE SOMEONE PICK UP MY JAW,” “oh. my. gosh. what, what what, what what .l,” and “MOTHER WHATTT❤️❤️❤️❤️.”

While it’s impossible to know what truly caused the mark on Swift’s neck, fans were loving the possibility that it was from Kelce, such as one who wrote, “DAYUM GORLY!!! LOVIN LOUDLY AND IM HERE FOR IT.”

Swift is finishing up her shows in Sweden before heading to Portugal next, but before her stop in Stockholm, she embarked on a relaxing Italian getaway with Kelce. The football player flew to Paris, France, to support his girlfriend at her show there before they enjoyed her few days off together.

It’s unclear when Kelce will join Swift on tour again, but she has many more dates to go, with spots in Spain, the United Kingdom, Switzerland, Germany and more.