Britain was still acquainting itself with Tony Blair (Michael Sheen), the country’s youngest prime minister in 170 years, when Diana, Princess of Wales, died in a car crash in Paris on Aug. 31, 1997.

The accident was a shock to the world, but no member of the Commonwealth was prepared for the cold reception the tragedy received by Queen Elizabeth II (Helen Mirren) and the royal family.

Preserving what she believed to be the family’s honorable image in serving its country, the queen steels herself against what Peter Morgan’s (“The Last King of Scotland”) bold script calls “heart-on-your-sleeve displays of emotion,” going as far as removing all televisions and radios from the home to shield young princes William and Henry from the news. As history knows, the reaction from the public, Blair and even Prince Charles (Alex Jennings) questioned the appropriateness of the queen’s believed outmoded conduct.

But Stephen Frears’ fictionalized biopic of the queen introduces this charming point in defense: lay off, OK! She’s the bloody queen, for Christ’s sake.

The dramatization takes place 45 years and nine prime ministers after the queen’s coronation. The head of the monarchy is seeing her very cultural criterion shifting toward a more “modern” paradigm in which Elton John and Tom Cruise brush elbows with royal blood and the entire system seems geared toward the public relations game.

But, let us remind you (as she sharply does to Mr. Blair) that this is the woman who advised Winston Churchill when he was prime minister. Her comment both challenges Blair and suggests to detractors that if these methods worked for Churchill, they should certainly work for Blair. Go figure – that head’s not just there for resting crowns; this queen’s a deceptively busy lady.

And the queen that Frears directs and Mirren embodies is impeccably complex.

Mirren’s every dense, contemplative stare is a telling portrait of the weight she must bear atop her prominent, neatly coiffed head.

When news of the accident arrives, she’s portrayed as curious, if somewhat disinterested. But, upon report of Diana’s death, her stoic expression glosses over and her heart seems to close as she and her family retreat to their beautifully shot Balmoral estate on the Scottish countryside.

Meanwhile, the country pours its heart and flowers over Kensington Palace and Mr. Blair warms up to the public (and eventually the queen) by providing the compassionate voice not registered by the royalty.

As serious as the content is – the potential fall of a nearly 400-year-old monarchy – count on the Brits to infuse it with subtle drops of humor, like the Queen Mother’s (Sylvia Syms) whimsical alarm at the suggestions for her altered funeral plans to befit the late princess’ celebrity status. Prince Phillip (James Cromwell) also throws in an untimely word or two about hunting and homosexuals whenever he should be concerned with the state of affairs.

The drama reaches its historical end when the queen delivers her famous speech to the public after five days of silence in the wake of Diana’s death.

When the royal family arrives outside Westminster to observe Diana’s memorial, decades of stalwart monarchic rule break ever so slightly in Mirren’s sharp blue eyes before reassuming that brazen veneer required of the noblest of the noblesse oblige.

It’s that moment in drama when everything must be just right – acting, directing, scriptwriting, everything – and it is.

Frears and Mirren have made a preeminent example of dramatic, character-driven filmmaking, but what else would you expect of the queen?