The Topless Tour/Barcroft Media/Landov

Lydia Buckler, Olivia Edginton and Ingvild Olsen have become internet stars by taking pictures of themselves with their shirts off, but the delightful photos are not what you may be expecting.

The trio have been on what they named "The Topless Tour" since December 2012, named so because they take revealing photos of themselves at each stop and post them on Instagram and Facebook.

"It all began around the biggest lake in Norway, Mjøsa, in 20-year-old Ingvild's hometown of Brumunddal," the trio told ABC News by email. "We had been for a walk around the lake and very spontaneously decided to see how cold we could really feel, as it was winter when we first lost our topless virginity."

"We soon became addicted," they wrote.

The key to the topless photos of the girls, all students at the Trinity Laban Conservatoire of Music & Dance, is that they are shot from behind, meaning you only see the girls' backs. Buckler, 21, is from Stratford-upon-Avon and Edginton, 20, is from Manchester.

"The 'Topless Tour' is the opening of your bare chest and heart to the world; but it is so much more than that, it's an experience," they wrote. "What is so wonderful is that underneath lies the powerful message of taking pride in our differences and embracing the love for the body."

In the nearly two years since the Tour began, the girls have amassed a following on social media, with over 8,000 likes on Facebook and over 13,000 followers on Instagram.

"We never imagined it would have such global reach and appreciation," they wrote. "We have received so many beautiful emails, people sharing their stories and photographs with us."

The founders have already posed in places like Berlin and London and say their next stops are Norway, Croatia and Sweden.

"The 'Topless Tour' isn't just our story anymore, it's becoming a part of so many adventures and lives," they wrote. "We think it's so lovely that so many people can experience and join in on our adventure and LOVE their bodies."