The MPAA has given Ang Lee's Toronto-bound "Lust, Caution" an NC-17 rating and Focus Features has accepted it.

The erotic espionage thriller, co-written by Focus CEO James Schamus and Wang Hui Ling, will bow in Gotham on Sept. 28, as skedded, and expand to additional markets Oct. 5.

Based on Eileen Change's short story about a shy Chinese drama student drawn into an assassination plot against a Japanese collaborator during WWII, the Chinese-language pic stars Tony Leung and newcomer Tang Wei.

Schamus said the specialty label accepts the rating without protest.

"As with so many of his previous films, Oscar-winning director Ang Lee has crafted a masterpiece about and for grown-ups, Schamus said.

The rating likely did not come as a surprise to Focus. In the pic's production notes, Schamus likened the lead femme character to Maria Schneider's role in "Last Tango in Paris," another sexually explicit pic that received an X rating for its 1973 release and was subsequently rated NC-17 for a homevideo reissue.

The MPAA created the NC-17 rating in 1990 in an attempt to remove the stigma surrounding the X rating. However, studios often fight the designation due to a due to newspaper advertising restrictions against NC 17 fare.

The MPAA ratings board cited the film's graphic sexuality for its decision. A source said too many of the film's sex scenes violated the ratings board's unwritten rules (like the number of allowable pelvic thrusts, for example) to make an appeal possible.

Sources who have seen the film said it contains at least three scenes -- one a long montage -- featuring multiple acts of aggressive sexual activity in different positions. There's no full-frontal male nudity (the source of some NC-17 rulings when shown in sex scenes), but male-on-female oral sex, non-S&M restraints and several nontraditional sexual positions are depicted, conveying the aggression and emotional conflict between the main characters.

When asked if anyone was shown, say, upside down, one viewer said, "It depends on where you're standing. They're very flexible."

i just love the idea of a film rating changing over the number of pelvic thrusts. its priceless.

That NC-17 sure made me think this would be a lot more titillating than the end result.