She’s Michelle Williams, the talented, reliably realistic actress acclaimed for her solid work in “Brokeback Mountain,” “I’m Not There,“ “Wendy and Lucy,” “Shutter Island” and  “Blue Valentine.”  Astonishingly, in “My Week With Marilyn,” she’s playing the breathless, bubbly,  tragically vulnerable sex goddess who reached her cinematic peak in Billy Wilder’s 1959 comic masterpiece, “Some Like It Hot.”

This new faux biopic is set two years earlier, the year of “The Prince and the Showgirl,” a frothy but strained screen adaptation of Terence Rattigan’s play that paired Monroe with Laurence Olivier. Sir Laurence played a suave but predatory Balkan royal determined to seduce American lady-of-the-chorus Monroe at the time of the 1911 coronation in London. To make sure that this spectacularly odd couple would come across as credible, executive producer (!) Monroe snared Olivier as director.

The focus of “My Week With Marilyn,” directed by Simon Curtis, is on the behind-the-scenes chemistry—or lack thereof—between these two exceedingly major players. Kenneth Branagh plays Olivier to Williams’ Monroe. Dougray Scott is cast as playwright Arthur Miller, the husband of Monroe; Olivier’s wife, Vivien Leigh, is acted by Julia Ormond. If the movie's a hit, perhaps the sexier-than-ever Michelle will treat us to updated versions of "Gentlemen Prefer Blondes," or even "Some Like It Hot." –Guy Flatley Opening date to be announced