Because of her strict Catholic upbringing, the actress has never taken her clothes off before the camera. In the film We Own the Night, Mendes has a sex scene with her co-star, Joaquin Phoenix. The actress revealed that she was so nervous during the scene, that she had a few drinks to help calm herself. Mendes said, "I was cringing the entire time we were shooting it. I was scared about doing it and I’m still like, ‘Oh my God, Dad cannot see this movie, Dad cannot see this movie! He would be mortified if he saw it."
The actress added, "I guess there is this little Catholic girl still inside me somewhere because otherwise I would probably have had no problem with that scene."