Whaaat...even the sexy pairing of Brad Pitt and Angelina Jolie in Mr & Mrs Smith didn't work?

If you think sex works all the time, you’re in for a surprise – sex doesn’t sell – nor impress, as far as the movie box office is concerned, according to a new a study done by the experts in the University of California, Davis (UCD).

In an interview with CNN, the study’s authors, who spent four years researching more than 900 films released between 2001 and 2005, proved that all the box office biggies during that period contained little or no sex and nudity at all.

“Sex did not sell, whether in the domestic or international box office, and even after controlling for MPAA rating,” said co-author of Sex Doesn’t Sell – Nor Impress, Dean Keith Simonton, a professor of psychology at UCD, one of the top public research universities in the US.

“In other words, even among R(-rated) movies, less graphic sex is better,” he concluded.

Co-author Anemone Cerridwen added that the study was developed based on her personal experience taking on acting classes, and how she was perturbed by the sexual content of the scripts she was given.

“I assumed sex sold, and wanted to know by how much,” Cerridwen told CNN. “I braced myself for the worst, and got quite the surprise.”

The academician hopes that the study will influence Hollywood producers. “I do believe that there are a fair number of people in the film industry who want to make better films, and this study may give them some ammunition,” Cerridwen said.