If there was one big surprise at last week's Emmy Awards, it was that Bryan Cranston walked away empty-handed. Sure, he's already got a trio of the trophies, recognising his work on Breaking Bad's first three seasons, and the series itself was finally awarded Best Drama, but Cranston's inhabitation of the character of Walter White as he evolves from a tired, miserable schoolteacher into a flint-faced drug lord has emerged as TV acting's new high watermark.
The series' showrunner Vince Gilligan says that the performance has influenced everything from the writing to the editing - lines could be cut, because thoughts were so clearly etched on the actor's face - but Cranston, for his part, is humble. "It's the most wonderful playground for an actor," he says of the role. "I love [Walt's] complexity and the sheer range of justifiable emotions that he experiences - from frustration to depression to aggression to fits of anger to jealousy to pride to hubris to avarice."
There's a sequence in the episode Ozymandias that shows how effortlessly Cranston can switch between these modes: we jump back in time to Jesse and Walt's first cook and it's a shock how different he looks. There's the slumped shoulders, the downturned mouth, the frown-lines, the weariness. Moments later and we're in the present again, with Walt transformed into Heisenberg, steely-eyed and commanding.
While the arc of the show's five seasons is to gradually erode any sympathy that viewers might feel for its central character, Cranston still sees things from Walt's perspective - which is crucial, Gilligan has said, to the way that he plays it.
"The whole point is that he's doing it for his family," Cranston says of his character's growing catalogue of crime. "He thinks: if I don't have much future in this life, then at least let me leave something for my family, so my children can go to college and my wife doesn't go short. Everyone feels that sense of responsibility, that desire to provide for the family."
What happens in the finale, after being roundly and irrevocably shunned by that family - told by his son that he'd be better off dead - is the topic of feverish fan speculation.
Rumours are also swirling about a follow-up movie, stoked inadvertently by Cranston himself. "They began on the red carpet," he says, "when a journalist said to me: 'They made a couple of X-Files movies. Would you like to do a movie of Breaking Bad?' I replied: 'I suppose I would, if there was a story to tell and not everyone was dead!' Before I knew it, that had become: 'I hear you're doing a movie of Breaking Bad. When's it coming out?'"
In the meantime, Cranston has already signed on to other projects. He's playing the former US president Lyndon B Johnson in a play called All the Way in Boston until mid-October and he'll star in a big-budget remake of Godzilla that's due out next year - but he's not expecting lightning to strike twice. "I'll never have a greater role than Walter White," he says, "and I'm OK with that. This is the greatest role of my life."
At the show's wrap party, he had the programme's logo tattooed on his right ring finger.
. The series finale of Breaking Bad is at 11pm, Tuesday on OSN First HD