So there’s Dustin Hoffman, strolling across the red carpet, his lovely wife on his arm, heading to the London Film Festival premiere of Quartet, his very first effort as a feature filmmaker.

And along comes a TV reporter, microphone in hand, ready to toss the inevitable softball question: How does it feel — at long last, after 45 years of acting in movies – to have finally directed one?

Hoffman, cheeky devil that he is, can’t help himself. Smirking brazenly, he replies: “It’s kind of like sex. The hornier you get, the better it is when it happens.”

Bada-boom!

But seriously folks: Quartet — which the Houston Cinema Arts Festival will screen at 7 pm Sunday at Sundance Cinemas — really and truly is the fulfillment of a longtime ambition for the two-time Oscar-winning actor.

Back in 1978, Hoffman almost made it happen when he set out to direct himself in Straight Time, a gritty drama about an incorrigible career criminal. But as he has ruefully noted in several interviews over the years, he fired himself, and hired Ulu Grosbard as his replacement, shortly after production began. Why? At the time, he did not have access to video playback, so there was no way he could objectively judge his own performance.

“In retrospect,” he says on the Straight Time DVD commentary track, “I’m sorry that I didn’t direct it. I think I just lacked the courage.”

But he didn’t lack second chances. Indeed, Hoffman freely admits he had several other opportunities to be an auteur before Quartet came his way.

“I’ve come so close to directing films over the years,” he said at the London Film Festival. “But I’ve always pulled out, thinking, ‘Oh, the script isn’t right, the script isn’t right.’

“And finally, my wife told me, ‘Look, if you wait for the script to be right, you’ll never direct anything. Because the script is never completely right.’

“So ultimately, I just had to say, ‘I’m going to do this.’”

It all came about thanks to a fortuitous entwining of coincidences. While filming Last Chance Harvey — in London, by the way — Hoffman casually mentioned to cinematographer John de Borman that he was looking for a script suitable for his long-delayed directorial debut. Not so long afterwards, de Borman was told by producer Finola Dwyer that she was looking for someone to direct a really great script she had optioned.

One thing led to another, Hoffman was sent a copy of the script — and what had heretofore seemed only a possibility started to look like an inevitability.

“I think they originally had one or two directors in mind,” Hoffman recalled two months ago after a Toronto Film Festival screening, “but they fell out or whatever. So I called Finola and asked if she’d consider me.

“And she said, ‘Let me think about it.’”

She didn’t have to think very long.

It took even less time for Hoffman to attract a stellar array of British acting greats with the script by Oscar-winning screenwriter Ronald Harwood (TheDresser, The Pianist).

Based on Harwood’s own stage play of the same title, Quartet is a seriocomic tale of harmony achieved by discordant characters. Specifically, it is a story about the residents of Beecham House, an English countryside retirement home for classical music artists.

Wilf (Billy Connolly), Reggie (Tom Courtenay) and Cissy (Pauline Collins) are enjoying their golden years in relative peace and comfort when their lives are disrupted by the arrival of a new Beecham House guest: Jean (Maggie Smith), a self-dramatizing diva who used to be their partner in a vocal quartet — and, not incidentally, Reggie’s partner in marriage.

The plot pivots on efforts to reunite the quartet for a fund-raising performance to benefit the retirement home. But that’s more or less a mere excuse to entertain the audience with the spirited interplay among the four lead players and their interactions with co-star Michael Gambon (Smith’s partner in the Harry Potter franchise).

As Quartet continues to earn rave reviews and generate Oscar buzz while touring the international festival circuit — last week Denver, this week H-Town — Dustin Hoffman finds himself, at the ripe young age of 75, earning kudos as a promising newcomer. No kidding: Last month, he received a special Hollywood Breakthrough Director Award at the 16^th annual Hollywood Film Awards.

“Actually,” Hoffman says, “I think some of the best directors have been actors.” The secret of their success? Recognizing the value of rehearsal as a key part of the creative process. And giving actors — as Hoffman did during the production of Quartet — the time they need to prepare their performances.

“See, I think the one thing that actors have in common, which directors are not always sensitive to, is that we are asked to get it right immediately. All the time is spent lighting the scene, deciding what the set is. And the actors are sitting in their campers or the makeup room or whatever, until someone comes in and says, ‘OK, everything else is ready — now we’re ready for you.’ So you come on, and they expect you to get it right away.

“Anyone who’s creative — whether it’s painters or writers, but particularly actors — you should be allowed a chance to fail. And fail. And fail. And fail until you fail better.

“And that’s what we did here. We just said, ‘OK, just let them alone, and give them a chance to find it.’ And they did, because their instincts are organic. And I will never be as thankful as I am now, having had the opportunities with these great, great artists.”

So the entire experience was an unadulterated delight? Well, not quite. But, then again, Hoffman never expected it to be. He was given fair warning ahead of time by no less an expert than Steven Spielberg.

“Steven told me that, from the very beginning, on every film he’s ever directed, when he’s on his way over to the set on the first day of filming, he has to pull his car over and throw up.

“It’s that nerve-racking.”