Will Ferrell, best known for playing overgrown frat boys, bubbleheaded anchormen and spoiled athletes, seems an unlikely Broadway angel. But the comedian has performed a minor miracle with “You’re Welcome, America. A Final Night With George W. Bush,” a sold-out hit on the Manhattan theater scene based almost entirely on a decade-old impersonation that should be about as relevant now as an Abbott and Costello routine.

But the 90-minute production, which HBO will present live Saturday, one night before the show closes, has struck a chord with audiences who can’t resist sharing one last laugh at the 43rd president’s expense.

Director Adam McKay says he understands that some fans will feel it’s time to move on, but that just as many aren’t quite ready to put the past eight years behind them.

“It seems like in our country, we tend to want to blow past stuff, like Ronald Reagan and the Iran-Contra controversy,” he said. “I think it’s kind of exciting that we’re not letting this go. Even though it’s a silly show, I think it’s healthy in a sense.”

The most important person who needed convincing was Ferrell, who stumbled into the impression on “Saturday Night Live” when Bush was a long-shot candidate. Speculation at the time was that Al Gore would win the election, putting the show’s master impressionist, Darrell Hammond, in the spotlight. Ferrell would occasionally do a walk-on, portraying Bush as a high-fiving, backslapping good ol’ boy.

“I thought, ‘Well, this will be fun, but he probably won’t win, so I’ll play him for a couple months and that will be that,’” Ferrell said. “Then he eventually won and he just kept kind of gaining momentum in terms of his comedic persona. There was this incredible combination of insane news events that he had to deal with and obviously some poor decisions on his part, along with his type of personality and the fact that he kind of can’t speak properly. That, you know, makes for a wonderful kind of comedic stew. I like to use the word ‘stew’ whenever I can.”

Hail to the chiefs

Over the past 34 years, “Saturday Night Live” has sent up every commander in chief, and not always with the same degree of success. Here’s a look back at the best and not-so-brightest.

CHEVY CHASE AS GERALD FORD

His take: An inarticulate, clueless klutz who can’t even support himself at a podium.

Our take: Chase’s physical shtick had about as much political bite as a banana peel.

DAN AYKROYD AS JIMMY CARTER

His take: An unflappable genius who can do everything from fix a letter sorter to talk down an LSD user.

Our take: A funny but fleeting idea.

PHIL HARTMAN AS RONALD REAGAN

His take: An evil mastermind who acts dumb only to fool the public.

Our take: Hartman’s ability to switch gears at the drop of a jellybean continues to amaze.

DANA CARVEY AS GEORGE H.W. BUSH

His take: Good-natured optimist with more hand gestures than an air-traffic controller.

Our take: Carvey’s enthusiasm was impossible to resist.

PHIL HARTMAN AS BILL CLINTON

His take: A Southern charmer with an equal appetite for women and Big Macs.

Our take: Bubbalicious.

WILL FERRELL AS GEORGE W. BUSH

His take: An empty-headed overachiever who acts like he’s president — of his fraternity.

Our take: The clueless-crusader act got about as creaky as the last hour of “Semi-Pro.”

FRED ARMISEN AS BARACK OBAMA

His take: Super-serious, super-stiff nerd.

Our take: Super-serious, super-boring.

Ferrell’s farewell

When: 9 p.m. Saturday

Where: HBO