Since the release of his last two films - American Gangster and The Great Debaters - in 2007, the Oscar-winning star has enjoyed a rare period of peace, away from the glare of publicity and the demand for interviews.
"I haven't done press in a year and a half and haven't sat down with anyone since the last movie came out. Between films I just get on with my normal life," says the 54-year-old, proudly.
Washington, who has been married to wife Pauletta for 25 years and has four grown-up children, is clear on how he has achieved what many celebrities can only dream of - managing to live his personal life in private and not splashed all over the tabloids.
"My life is really kind of regular and private and normal," he admits, with an unapologetic shrug.
"It's just not interesting for the press to write about. The tabloids don't write about that because it doesn't sell newspapers."
The sole reason why he is doing interviews today is to promote his new nail-biting thriller, The Taking Of Pelham 123.
In the remake of the 1974 movie, he plays Walter Garber, a New York City subway dispatcher who gets caught up in the middle of hostage negotiations during a subway hijacking.
"After playing Frank Lucas in American Gangster, I wasn't looking to play a big-time drug dealer next and that was my only criteria for this one," he explains.
"I liked that my character had a regular marriage too, with a woman who supported and loved him."
The respected actor-director, who has two Oscar trophies adorning his mantelpiece at home, is almost unrecognisable because he had to pile on the pounds to play Walter, an opportunity he made the most of.
"I had been heading that way and so I went with it and kept going," Washington reveals, laughing.
"You just don't exercise, eat late and have that burger and all the fries and the shake and dessert and you can get there really easy!"
He adds: "I embraced it and really liked that aspect of this character that made him human and normal and struggling with the same things we all struggle with. He's overweight, he's clumsy, but he's a decent guy. I don't even think he realises he's overweight, but it comes with the job."
The extra weight - combined with a recent operation - posed a few problems for the middle-aged actor, especially during the running scenes.
"I had just had knee surgery and it was heavily wrapped and the last thing the doctor said was, 'Now don't do any running!'" he recalls.
"When you see me run, that is 18 or 19 takes of me running really hard so that was challenging because then your ego is involved and you are thinking, 'I can't be out here huffing and puffing and looking bad', even though I'm overweight and had surgery. So I'm thinking, 'Wait, I have to have some sense of style and grace about this!'"
Washington, who was raised in New York but now lives in Los Angeles, admits he enjoyed returning to his home town for the shoot.
"I've done a lot of movies in New York and to me, it was like home," he reminisces.
"I grew up in New York and subways were the way to get around so I spent many many hours on subways as a kid. Just to sit there and remember days when I was a kid and didn't have enough money to get on the train and I would have to sneak on, and now I am sitting there at the same subway stations in a hundred million-dollar movie. Life is so interesting."
The actor also had fun exploring the underground maze of the subway: "As a kid you always wanted to go down there and I had done that, but you never went too far back then, because it was the unknown."
But the actor admits the film made him break a childhood promise about revisiting the subway.
"I hadn't taken the subway in more than 20 years because I used to spend two hours each way on it every day going to school and back and did everything on it - slept, ate, homework - and I swore as soon as I had two pennies to rub together, I would never ride it again and I didn't! Until this movie of course."
He has no inclination to ride it ever again. "No, I did enough subways on this film over five months and it smells just the same as I remember it," he says, with a hearty laugh.
"But it was cleaner than it used to be and I didn't see any rats, which surprised me, but I think they were all scared off by the noise with the lighting guys and the crew who would get down there before me."
While his knowledge of the New York subway above ground was sound, Washington needed professional training before he could go underground.
"It was trippy. You had to take a full eight-hour safety course so that was a real introduction," he says.
"I learnt that the third rail is very dangerous. They showed you pictures of what happens to people - they fry and it's not nice - but what happens is you relax after a few weeks or months, so I made sure not to."
He adds: "They were turning power on and off for us all the time but I kept acting like the power was always on. It can be a very dangerous place to be down on those tracks and you have to always be on your toes if you want to stay alive."
The Taking Of Pelham 123 teams Washington with John Travolta for their first on-screen adventure together.
"It was fun because he was a really sweet person, one of the nicest people I've ever worked with," he says.
"I didn't know him but I'd met him before. It was an interesting relationship and interesting the way it developed, the way it did in the film."
This "interesting" relationship included the duo singing their hearts out to one another in between filming the edge-of-your-seat drama - a bizarre situation given the circumstances.
"Between takes on the microphone, we would sing songs and tell jokes. Somewhere along the line, there will be a tape that will come out of Denzel's greatest hits with John and I doing a duet!"
Washington, who received Academy Awards for his starring roles in Training Day and Glory, has been more hands-on behind the scenes, and sat in the director's chair for Antwone Fisher and The Great Debaters.
With an unblemished track record, he admits he never scrutinises his past work.
"I don't think back. What I've done is done, the past is the past and I don't believe in looking back," he says.
"A thought might come into my head occasionally about what I did and why but I don't sit around trying to look for a reason. If you are looking for a reason, you'll find one - but it doesn't mean it's the right one!"
He adds: "All I care about is decent material. It's no mystery, you just read it and ask yourself if you like it, is it something interesting?
"But it's all about the material. If it ain't on the page, it ain't on the stage!"
Extra time - Denzel Washington
Denzel Hayes Washington Jr was born on December 28, 1954.
He started acting in theatre before getting his big break in TV hospital drama St Elsewhere.
He is the second African American man - after Sidney Poitier - to win the Academy Award for Best Actor, which he received for his role in 2001's Training Day.
He holds the record for most Oscar nominations by an actor of African descent: so far he has earned five.
He remains unfazed by his star status, saying: "Acting is just a way of making a living, the family is life."