WHO’S that platinum blond with the chorus-girl gams – in black tights, white shirt and little else – who’s been the hottest ticket on Broadway?

The one who just took home a Tony for her one-woman show? (Memo to Tony producers: What made you think she’d demurely cut her acceptance speech short, just because the music started?)

Britney Spears? Puh-lease. Madonna? Over in England. Rudy, back in town? Guess again.

It’s Elaine Stritch – who turned 77 this year.

The talk of the Great White Way for her smash hit, “Elaine Stritch: At Liberty,” Stritch is proof your mother was right: You can succeed through hard work, determination and a fair amount of talent.

Those under 40 might remember her from “The Cosby Show” as Rudy’s elementary school teacher, or from Woody Allen’s “September.” But the Broadway Baby hit it big in shows like “Pal Joey,” “Bus Stop,” “Sail Away” and “Company.” In the ’90s came “Show Boat and “A Delicate Balance.”

What sweet irony: This woman’s been knocked around – hard. But “Stritchie,” as Noel Coward liked to call her, finally finds herself “at liberty” to tell the world her dirty little secrets.

Like depending on the bottle – for decades. It wasn’t until she was a senior citizen that she faced the stage straight.

When did she discover that the world was a little brighter and laughed harder at her jokes when she drank? The ripe old age of 9.

“I’m angry. I’ll get over it. But I am. Sore as hell that I had to go through what I had to go through to get through what I had to get through,” she says in her play.

“You know what helped? What really helped? Booze. It’s scary up here. So for 58 (or 59) of those years . . . I never set foot on a stage without a drink! Or any place else, come to think of it.”

She hated not being pretty, even more so on the stage. It’s not easy being in show business if you’re no great beauty.

And she went through plenty before she found the love of her life – British actor John Bay.

“My joy was overpowering,” Stritch tells the audience. “John was comin’ back here – to stay – with me. And he did. He came back, and he stayed with me for 10 years.”

Until he died of cancer.

“I loved being married. I’d love to be married again. But I just can’t find him – not anywhere. Not even close.”

It was probably the most poignant line of the play.

The only way Stritch could have made it so far was to fall so very low.

Yet there she is – in a world of teen models, reality TV and Britney Spears – singing “I’m Still Here” in a smash hit that was impossible to get tickets for.

You can’t buy her kind of life experience.

“At Liberty” has no set, no other actors, no costume changes. It’s just a chair, Stritch and that voice – whose every gravely rasp has been earned – talking about love and singing about the blues.

Now, the idea of seeing a “wise-cracking, old broad doing Broadway” hardly sounds appealling. But what audiences got was exceptional talent and a moving recollection of that same neurotic drive to self-destruction that so many young folks think only they know. (Who hasn’t felt rejection, loneliness, the need to be loved?)

How fortunate the world got to know her in this role. “At Liberty” was the ultimate victory for style and substance: Theater-goers bypassed high-wattage shows, like “The Graduate,” with big-name casts. What they got was the joy and inspiration of that funny “old broad,” Elaine Stritch.