Staff of the Anne Frank House in Amsterdam, where Frank and family hid from the Nazis until they were betrayed in 1944, posted on Facebook that Bieber visited the landmark building.
The staff noted that Bieber signed the museum's guestbook with, "Truly inspiring to be able to come here. Anne was a great girl. Hopefully she would have been a belieber."
Facebook readers were not happy with Bieber's assumption.
"She would've been a WHAT?" wrote Kevin Garcia Leon. "That little idiot is way too full of himself. She's an important historical figure so show some respect."
"Way to turn an inspiring moment into something about yourself," wrote Meghan Mausteller.
On Monday, the Anne Frank House defended Bieber on the museum's Facebook page, with staff writing, "The Anne Frank House was pleased to welcome Justin Bieber to the Anne Frank House last Friday. We think it is very positive that he took the time and effort to visit our museum. He was very interested in the story of Anne Frank and stayed for over an hour. We hope that his visit will inspire his fans to learn more about her life and hopefully read the diary."
According to the Facebook page, fans waited outside the Amsterdam landmark just to see Bieber, who was in The Netherlands for a concert.