In Jack Irish: Dead Point, a telemovie full of fantastic performances, two moments of acting-without-words stand out. One is the final scene involving Kat Stewart as a mysterious club owner, where her expression reveals the complexity of her attitude to what Irish is doing. It's the kind of layered performance we've come to expect from Stewart.
The other standout moment might surprise some viewers. It comes from Shane Jacobson, still known to most Australians as Kenny.
Private investigator Irish is thrown into jail after a battered body is found in the boot of his car. The detective who turns up to interrogate him is Irish's old mate Barry Tregear, played by Jacobson, whose face must signal Jack that he is not supposed to know him.
''You've got to act a scene where you're pretending to act normal, if that makes sense,'' says Jacobson. ''You can't look at him as you would if he's a guilty man and you're about to interrogate him. You start to layer it up. I'm supposed to look at him like we've got to pretend we're not friends.''
Jacobson never trained as an actor, though he's been performing since the age of eight. He says he's now reached the point where he is as comfortable doing drama as doing comedy, and he takes his performances very seriously.
Barry Tregear, who can best be described as a lazy slob, is one of his three favourite characters (along with Kenny - ''he's been such a great mate to me in my career'' - and Luce in The Time of Our Lives).
''I find Barry amusing, but I don't play him as comedy,'' says Jacobson. ''I had plenty to draw on. I felt I had met so many people like him, big burly blokes, friends of my dad or my uncle, always going on about some bastard this and some prick that. They were incredibly dry, but they never cracked a smile.''
Jacobson had no trouble resisting the comedy writer's temptation to improvise. ''With a Jack Irish story, you're working with Peter Temple's words and the guy's a genius,'' says Jacobson.
''There's so few people who can write something that really does feel very Australian without having corks on strings hanging from a hat. Improvising would be like me offering to put one more stroke of paint on the Mona Lisa.''
He says he has been inspired to work harder on his performances by working alongside great actors such as Claudia Karvan, Justine Clark, and Guy Pearce. When I remark that he has not yet demonstrated he can do an American accent as convincingly as Pearce, Jacobson offers a revelation:
''Well, I did play an American named Bob [pronounced Bahb] in a sketch we did for Movie 43. There were about 12 or so short films in that, but mine at the last moment got taken out.''
Wait, Movie 43, wasn't that the one described by many critics as one of the 10 worst movies of all time, in which Naomi Watts played a mother teaching her teenage son to tongue-kiss? Yes, says Jacobson quietly, that was the one: ''It got quite a slamming from the entertainment media.''
So his contribution to Movie 43, the one opportunity he's had to show off his American accent, was not good enough to go in the worst movie of 2013? ''It does sound like it. Believe it or not, they actually thought the material was too confronting.''
This was in a movie where Hugh Jackman had testicles hanging from his chin? ''Yes, it was even too much for that.''
What was it that Jacobson was doing? ''If I tell you, I think it will turn people off your article. They don't want to read this. It wasn't any actions of mine. It was something done by another actor. He was just an unsavoury character.''
And at this point amiable Shane Jacobson, usually happy to joke around about anything, refuses to say more, leaving us to speculate on what will doubtless become one of the great mysteries of 21st century showbiz.
Jack Irish: Dead Point is on ABC1 tonight at 8.30.
For more details, go to theage.com.au/entertainment/blog/the-tribal-mind