They’re just different.

If anything confirmed for me how very different the current crop of activist and committed movie stars is from those of the past, it was last week’s rather stunning announcement by Angelina Jolie of her double mastectomy in an op-ed piece in the New York Times.

Not in People, or In Touch or with Diane Sawyer or Barbara Walters, but in an op-ed piece in the Times.

As Jolie explained it, the decision – as momentous as it was for a star whose career has involved so much glamour and physical display – seemed simple enough.

Doctors had told her that because of genetic predisposition, she had an 87 percent chance of getting breast cancer and a 50 percent chance of ovarian cancer. Her genetic “defect,” she told the world, results in cancer 65 percent of the time.

“I hope that other women can benefit from my experience,” she wrote. “Cancer is still a word that strikes fear into people’s hearts, producing a deep sense of powerlessness. But today it is possible to find out through a blood test whether you are highly susceptible to breast and ovarian cancer and then take action.”

She turned her private decision, then, into part of America’s public education. I don’t know that I’ve admired such a public rendering of the most private medical matters since Betty Ford told the world she was going into rehab, thereby changing entirely how America would think about addiction.

There were too many women in the world – and their families – who needed to know that even an actress of such vaunted sensuality could choose her life with her children over show business exploitation.

It’s what the best of her generation seems to do – George Clooney, for sure, but also her husband, Brad Pitt, and Matt Damon. They put their films – and their very lives – in service to higher ideals and the world if they can.

They know that the minute they walk into a Los Angeles Von’s Market or a Trader Joe’s for an avocado or a liter of coconut water there will be a flurry of cellphone photos and text messages and social media pronunciamentos. Their fame is different from that of earlier Hollywood generations. (And so are its transmission systems.)

I once watched Marlon Brando being maneuvered through Los Angeles airport by a dense cloud of blond women (his personal assistant and her daughters, it turned out), and as much of a commotion as it stirred in LAX, back then it wasn’t instant fodder for an entire Internet world.

If it had been Clooney or Pitt now, it would be. If it took too long, alerted paparazzi – so much denser in population than they used to be – would be on the scene to catch the star waiting patiently, as Brando did, for his entourage to retrieve his luggage from the carousel.

Their whole star generation is aware of the spotlight that accompanies them out into the world, wherever they go. So they put it to use in ways that even the Paul Newman/Robert Redford/Warren Beatty/Jane Fonda generation never did. (More carefully and wisely, certainly, than Fonda; more effectively than Brando; far more publicly than Beatty.)

They have no fear of bringing their sociopolitical beliefs into their films – or it seems their very lives into their very reasons for fame.

It’s almost as if a whole cautionary top layer of diffidence has been removed and we now have a generation of performers determined to detoxify the absurdities of fame with which they’re all too familiar.

Yes, it’s true that Jolie was set to star in a $200 million live-action “Sleeping Beauty” tale called “Malificent” to be released in July 2014. But when it came time to write and direct her own first film, it was “In the Land of Blood and Honey” about Bosnia, made with a Bosnian cast.

We won’t even mention playing Mariane Pearl in “A Mighty Heart” or her movie “Beyond Borders.” They’re a long way from “Wanted” and “Salt.” It’s as if she were telling the world, “OK, you care so much about my life with Brad, here is the reality of it. And here are some things we think about – a few more interesting realities – since you seem to care about nonsense.”

Clooney, of course, admits flat-out that he uses fame to call attention to world problems (in Darfur, say). When he makes films of his own, his family’s journalistic idealism is going to be poured into “Good Night and Good Luck.”

In “Promised Land,” Damon made a pretty good film about the business of “fracking.” In HBO’s upcoming “Behind the Candelabra” (see Saturday’s Buffalo News for a review), he plays Liberace’s live-in lover to Michael Douglas’ Liberace in a rare use of their high level of stardom by both actors. (In different ways, previous sets of straights playing homosexual lovers in movies – Heath Ledger and Jake Gyllenhaal in “Brokeback Mountain” and Richard Burton and Rex Harrison in “Staircase” – were at different stages of their careers.)

There is, of course, the ancient argument that actors – whose profession, after all, is pretending to be what they are decidedly not – should keep their lives and opinions about everything to themselves and leave thinking to others much better equipped to do it in public.

What if, after all, some of those actors are conspicuously smarter than so many others whom society entrusts to think out loud?

Is there any serious journalist who’s sorry Clooney made “Good Night and Good Luck”?

Is there anyone in any American family with some experience of cancer who doesn’t think Jolie did something useful and even heroic with the fame that had heretofore abused and mistreated her?

She made public what earlier generations of actresses would have kept as private as possible because – $200 million films or not – she jolly well knew her story would make it easier for others to save their own lives.

They seem to be a whole generation that knows exactly how ridiculous is the fame that a Kardashian society confers on them – until, that is, they use that fame to illuminate what the world seems to want hidden.

They know the secret of any spotlight – aiming it where it needs to go.