The hair is grey, rather than bleach-blond, and the jacket is grey too, rather than gold lamé, but the bright red wool tie is the same, as are the round-framed glasses and the infectious grin. While not quite as strikingly dressed as when he picked up his gold medal from the Royal College of Art in 1962 - with mocking gold jacket and locks to match - it's still unmistakably Mr David Hockney, now the UK's best-loved painter, on the eve of opening his largest exhibition in the UK to date.
Would that younger incarnation recognise the 74-year-old version of himself today, I ask. "Yes, basically I was a cheeky schoolboy then and still am. Most of my friends would think that too." A confident, young, gay man - the epitome of swinging 1960s London, despite having just arrived from provincial Bradford - Mr Hockney was even brazen enough at that time to print up his own mock degree certificate after the RCA threatened to fail him for non-attendance. "It was absurd because they were worried about what diploma to give me, but I told them they should be worried about what they were teaching." The school backtracked and lauded him as its most prized student as soon as it became clear that Mr Hockney would also be the most talked about artist of his generation.
His decision to quit England for America in 1966 came as something of a shock: "David Hockney, Britain's brightest young artist, has decided to leave Britain", ran the headline in The Sunday Times; "Pop artist pops off" was another. "The first time I went to New York was in 1961," recalls Mr Hockney, "and I must confess the moment I got there I thought, 'This is the place.' It was a more open, 24-hour city. I thought it was fantastic, that is, until I went to Los Angeles."
Seeking sun, sex and freedom, Mr Hockney soon developed a signature West Coast aesthetic through his portrayals of seedy LA street life and the famed pictures of swimming pools and showering boys. "When I went to LA, people told me I'd come to a cultural desert, but I didn't think so. Frankly, when someone tells me that Andy Warhol was the greatest visual artist of the 20th century in America, I say no, I think there's another much bigger - Walt Disney."
Mr Hockney in his Kensington studio as photographed by Lord Snowdon, London, 1978
In 1997, some 30 years after he first settled in sun-filled Malibu, Mr Hockney returned to his East Yorkshire roots to begin painting its winding lanes and ever-changing seasons - subjects which now form the spine of his major show at the Royal Academy of Arts, A Bigger Picture. "I'd always spend Christmases in Bridlington - me, my mother and my sister Margaret - as an only, unmarried son, you can't get out of it. I'd thought it was too dark, I mean you only have six hours of daylight in the winter." Nevertheless, he fell in love with the landscape that was familiar to him from childhood. "The great thing was finding a subject in a rather remote place, where I was left alone. In fact, we can live rather freely in Yorkshire because the office is in LA and they don't get there till six in the evening. Everything happens either in Bridlington or in Hollywood, so we now call it Bridlywood or Hollington."
Indeed, there is something approaching the bravura of cinematic production values in Mr Hockney's most recent forays into the fields and forests of the Yorkshire Wolds. Over the past decade he has produced his largest single works - giant, enveloping multi-partite canvas murals, measuring 40ft wide - as well as experiments with evermore sophisticated technologies, including a new nine-screen film. "Rather than standing still somewhere and looking at something, I started to take in the landscape as a driver quite a long time ago in Southern California, because of its bigger scale. And I did that in Yorkshire, too."
Mr Hockney has never seen things from one static, accepted position, preferring the multiple, non-linear perspective favoured by traditional Chinese artists who, he says, "looked at the world as a walk-through landscape, not through a hole or a window, like Europeans do, which is also the [view of] television or the camera". In the past, Mr Hockney has been a vociferous opponent of the oppressive nature of lens-based media: "To the Chinese, painting was always about the hand, the eye and the heart. Nothing could ever replace it. I mean how are we going to depict the world, just with photography? It would be rather dull and very restrictive if you know about cameras."
Woldgate Woods, 21, 23 & 29 November, 2006
Oil on six canvases 182 x 366cm. Courtesy of the artist. Photo: Richard Schmidt. Copyright David Hockney
Winter Timber, 2009
Oil on 15 canvases 274 x 609.6cm. Private collection. Photo: Jonathan Wilkinson. Copyright David Hockney
The Big Hawthorne, 2008
Oil on nine canvases 275.5 x 366cm. Courtesy of the artist. Photo: Richard Schmidt. Copyright David Hockney
The Road Across the Wolds, 1997
Oil on canvas 121 x 152cm. Private collection. Photo: Steve Oliver. Copyright David Hockney
A Closer Winter Tunnel, February - March, 2006
Oil on six canvases 182 x 365cm. Photo: Richard Schmidt. Copyright David Hockney/Collection of Art Gallery of New South Wales, Sydney
And yet here he is, the 21st-century pin-up boy for the iPad, a device he's been using obsessively since it was released in 2010. So much so, in fact, that the main room at the Royal Academy contains 51 giant iPad prints, nearly one a week for the past year that Mr Hockney has spent drawing the same spot on Woldgate, a road on the outskirts of Bridlington, Yorkshire - "I was painting as fast as possible, the way Van Gogh did," he says. How does he justify his sudden switch from paint to pixels? "There's no such thing as a worn-out subject, it's only the method of depicting the landscape that's worn-out - you find other methods. Every generation can do that. The moment chemical photography ended, we entered a new era of digital photography and Photoshop, which is really drawing. So, in a way the hand is being put back in the camera after the chemicals took it out in 1839."
The other pocket gizmo that has replaced Mr Hockney's usual pens and sketchbooks, the iPhone, goes off loudly and the increasingly deaf artist breaks off from our interview to discuss his health and the stresses of putting on this enormous show, with some physician or other of his, on the other end of the line: "When it's over I'm going to Baden-Baden for a spa." There's still something of the Los Angeleno in him, I suggest. "I haven't left LA. I point that out to my office using the Hollywood phrase, 'I'm on location'."
A Bigger Picture runs until 9 April at the Royal Academy of Arts, London