The 22-year-old was at the Los Angeles Premiere of the forthcoming wearing a backless dress which was slightly too revealing as she posed for photographers on the red carpet.
Embarrassingly the side of her dress slipped, but Watson had taken precautions for a possible malfunction as she was wearing adhesive covers, reported Daily Mail. Watson still looked amazing in her nude dress, and she wore dark eyeliner and classic red lipstick.
The movie is her first major role since the end of the 'Harry Potter' franchise and sees her portray a teenager who is part of a clique at a Pittsburgh school, and she admitted it was a "very voyeuristic experience"' compared to the wizard movie series.
"It felt pretty exotic to me. It really did. It was a very voyeuristic experience. Getting to go to Friday night football and Olive Garden, schooldances and all of that stuff. That was really another world to me," she said.