Although everyone expected the S&M-themed love movie “Fifty Shades of Grey” to receive an R rating, the reasons it actually got the rating has raised eyebrows. The MPAA gave the filmed an R rating in part because of “unusual behavior.”

In its decision, the MPAA, which rates all films released in the U.S., said the upcoming film has “strong sexual content including dialogue, some unusual behavior and graphic nudity,” according to Variety.

The film, set to be released on Feb.13, is an adaptation of E.L. James’s bestselling book of the same name. The book’s erotic content has made it widely popular and shone light unto bondage culture.

The rating allows anyone 17 years or older to view the movie, but anyone under 17 must be accompanied by an adult.

USA Today reports that according to film historian Leonard Maltin, the “unusual behavior” reasoning for an R rating is new.

"It's the newest euphemism," he said. "You could say that ‘Guardians of the Galaxy’ had 'unusual behavior' as well. But it's a nice turn of phrase."

Ethan Noble, chairman of MP Consulting, “a company which helps studios and producers navigate the ratings process with the MPAA,” according to USA Today, also said he had not heard the term before.

"Basically, it's a way of letting parents know that it's not your everyday sexual content," Noble posited. "But you don't put 'submission and dominance' in the ratings description. [The MPAA is] rarely that specific, and parents that don't know what it is might be scared off by the term."

Aside from the film’s R rating, fans of “Fifty Shades of Grey” also got other news recently. On Thursday, singer Ellie Goulding released the song “Love Me Like You Do,” Rolling Stone reports. The song joins The Weeknd’s “Earned It” and Beyonce’s remake of her hit “Crazy in Love” as part of the upcoming film.

 Listen to the song and say what you think about it in the comments: