He’s been on screen since he was seven – but only prepares for a scene 10 minutes before.Yet somehow the mischievous Succession star is now tipped for an Oscar.How did the chaotic, charismatic actor do it?Kieran Culkin tries the upright chair first, the one opposite me, high-backed and leather.But no, that’s no good.He can see his reflection in the wall mirror, he’ll be catching himself all interview, thinking how tired he looks with his hooded eyes and beard, how jet lagged.

Sleep is always tricky, but he’s been up with the kids – five and three – who weren’t supposed to join him for this publicity tour but there was a last-minute crisis, the short version of which is that the whole family is over from New York (with Culkin, 42, there’s always a long and short version),So, he flumps on the banquette, where he’ll be facing guests drinking afternoon cocktails in the low-lit, high-ceilinged bar here at the Corinthia hotel in London,He tests the firmness of the upholstery,Pantomimes boneless relaxation,Looks at me to gauge the distance between us.

No, this won’t do, either.He’s too low, these people are distracting and, proximity-wise, he’s a little close.He scrambles back to the chair.Grabs the drinks menu.Muses that you may as well have the expensive thing if you’re not paying, orders champagne plus whatever trimmings, strains to peek at my notes.

“Your fun notes.Notes I am not allowed to see.” He taps his phone screen, “OK, your time starts … now.” Cackles like a cartoon villain.“Yeah, just kidding.

”This rush of jagged energy he maintains for a full 90 minutes.It’s the engine of his anecdotes – he communicates in anecdote – delivered with an impressive range of gestures, accents, imitations.It can be disconcerting.My sense at all times is of being at a cliff edge.Later, he says, unprompted, “I’ve never done drugs, never done coke, I never did pills, never interested,” before correcting himself to say he smoked pot.

“Not for like, 20-plus years,” but as an out-of-control teen, he once spiked a prop spliff with actual marijuana in an off-Broadway play.The entire cast, including Mark Ruffalo and an older actor who had never smoked before, were blitzed.Oh, and also: it was press night.Most of us know Culkin – whose brother is Home Alone’s Macaulay – as Roman Roy, the caustic unfiltered “slime puppy”, youngest son of media baron Logan Roy in HBO’s hit series Succession.What Culkin brought to the role of grubby super-brat was a subtle vulnerability, bruised as well as bruiser.

Roman might have been incontinent with snark, with curse-studded truth grenades, but deep down we sensed churning torment and couldn’t take our eyes off him.No one was surprised when he won an Emmy, a Golden Globe, a Critics Choice award.Deadpan, he refers to the series as “suck session”, but God, he loved that show.He bawled when it ended.Shades of Roman’s disinhibited charm he brings to his latest role of Benji Kaplan in A Real Pain, written, directed and co-starring Jesse Eisenberg, who plays his cousin David.

The pair are cousins on a Holocaust tour in Poland, honouring their Grandma Dory who survived, “by a thousand miracles”, Majdanek death camp,Eisenberg, who was nominated for an Oscar for his portrayal of Mark Zuckerberg in 2010’s The Social Network, has described it as an American buddy road story, “but fraught”,Close as kids, the cousins are now out of sync: Benji is lightly manic, unable to keep zipped the guts of his inner chaos; David is medicated restraint,It’s a combustible dynamic – and funny (it won best script at Sundance and is gathering deserved Oscars’ hype),It was an online advert, “Holocaust Tour (with lunch)”, that gave Eisenberg the idea for his film.

He thought it absurd at first, then saw the comic potential.He had already worked on two characters with the David-Benji dynamic in plays, and 20 years back, had been on a trip to Poland to commemorate those in his own family killed by the Nazis.That Culkin isn’t Jewish was the first thing he brought up when he spoke to Eisenberg on the phone.“Jesse goes, ‘That doesn’t matter.’ I said, ‘Are you sure?’” As a consequence, he sees questions about non-Jews playing Jews as something for Eisenberg – “it’s his baby”.

(Eisenberg has since told New York magazine, “I have 17,000 thoughts about this, and where I come out is that [Culkin] gave me an amazing gift by helping to tell this story that is very personal for my family.”) Nonetheless, he visibly relaxes when I tell him that David Baddiel, author of Jews Don’t Count, was in the audience at last night’s screening and has praised him on Instagram: “Kieran Culkin is I’d say an early Oscars contender,” he wrote.Culkin asks me to repeat the title of Baddiel’s book and starts typing it into Notes, before halting.“OK, I am not writing that in my phone.Somebody might take it out of context.

”A reminder: Kieran was the fourth of the seven cow-licked and petal-skinned Culkin children, farmed into acting so young, they were almost their own elementary school brat pack.Now only he and his younger brother Rory are still in the business.(Macaulay has only made a handful of films since he was 14.For a time he hosted an eccentric podcast called Bunny Ears, but now mostly writes and paints, while raising his two sons with his partner, Brenda Song).A mark of how long Kieran has been acting is that his appearance, aged seven, alongside Macaulay in Home Alone (1990), was his second professional job.

Since then, he has appeared in scores of film, television and stage roles, including Father of the Bride (1991) and The Cider House Rules (1999).He developed his own brand of anguished delinquent in Igby Goes Down (2002) and The Dangerous Lives of Altar Boys (2002), and it was while filming Infinity Baby aged 33 that he realised acting was, in fact, his career.“I thought, ‘Oh, I guess this is what I’m going to do for a living because I have no other skills.I’m serious: I have literally nothing.I’m a high school dropout.

I don’t even know how the internet works,I have never had social media,I don’t know what LinkedIn is,I don’t know what Reddit is,I don’t know what things are and I’m supposed to get out in the world and get a job?’”Right now, Eisenberg is upstairs in this hotel building, but last night they had had their big London screening.

Culkin was exuberant because his Succession friends had come along.He drank martinis with J Smith-Cameron, who plays general counsel Gerri Kellman, with whom he has an inappropriate flirtation on the show, and hammed it up in front of a swooning superfan.Culkin had also been telling the show’s creator Jesse Armstrong how Eisenberg had hired him for the part of Benji without an audition.Eisenberg had never seen Succession, or anything else Culkin had been in, films or plays.“He’s like, ‘I’m aware of you.

I’ve met you before,’” Culkin says.“And I said, ‘Yeah, fucking twice in passing.’ I said he was very good in a movie.And he liked that.”Culkin leans in, tugging the hairs of his beard.

“So, Jesse Armstrong goes, ‘But, hold on: the movie lives or dies on who is cast as that part? I go, ‘Yeah.’ He goes, ‘So, I think that’s bullshit.I think he’s lying.I want to get to the bottom of it.’“What’s funny is, I then had to go and do a live Q&A and so I repeated all this to Jesse [Eisenberg] on stage.

I said: ‘Jesse Armstrong thinks you’re lying, and he wants to get to the bottom of it.’ He goes: ‘I’ll get to the bottom of it now.It’s absolutely true.’ I didn’t know Jesse Armstrong was by now sitting in the front row of the Q&A.He yells, ‘You’re lying.

’ I was like, ‘Oh, good, you guys can meet now.’” He collapses back in his chair laughing.It was, in fact, Eisenberg’s sister who, after he sent her 30 pages of script, said, “Hire Kieran Culkin.” But too much tickles Culkin about Eisenberg.He has perfected Eisenberg’s frown, head scratch and anxious-earnest way of speaking, and role-plays both their parts when relating their interactions.

Like the fact that during filming, Eisenberg would ask after every shot, “‘Did I look ugly in that?’ Specifically, ‘ugly’,‘Do I look like a person, or do I look ugly?’” Or the fact that Eisenberg is so perfectionist on set that he would “analyse everything, prepare everything; be a nervous wreck in the moment leading up to, including and after the thing he’s doing”,Culkin, by contrast, learns his lines minutes or even seconds before delivering them for real,He finds it impossible to stand on the mask-tape crosses on the floor, nor can he necessarily keep to the exact words in the script, or deliver the same temperature of performance each time the clapperboard snaps “because just on a whim, something else would happen in my body”,Days into filming, Eisenberg knocked on his trailer, looking perplexed.

“He kept asking me if I was nervous about something.I was like, ‘No.’“‘Do you need me to give you the script? You know the lines?’“‘I don’t know lines, but I will, don’t worry.’“‘We’re shooting in 10 minutes.’“‘I’ll know them.

Don’t worry.’ He thought I was kidding.I’m like: ‘I’ve read it, I know it’s good; I don’t want to think about it, I just want to do it.’ So Jesse takes a couple steps away and comes back.‘Did you think when we shot this that you and I would be alike?’“I go, ‘No.

Not at all.Why, did you think we would be alike?’“He goes, ‘I did.I did,’ and walks away scratching his head.”The waiter asks if Culkin wants to taste the champagne.“I’m sure it’s fine,” he says.

“I’m just going to drink it whatever.” He eats a few olives, and then says that, actually, he and Eisenberg do have similar sensibilities, similar tastes in film and theatre, a similar sense of humour – except that Eisenberg likes to lean away from a joke.He also adds, maybe because he doesn’t want to sound like a douche, that the way his brain works means he has to learn his lines rocket speed (an eidetic method that startled even Brian Cox, the veteran actor who played Logan Roy).Beyond that, his feel for his roles is instinctive.Meaning that he might throw out a line he feels the character might say – be it Roman or Benji.

Eisenberg has since said that while initially disorienting, some of the best scenes were shot in this way,Culkin absolutely does not want to talk about craft, or how he does what he does, or where his talent comes from,“If it’s working –” he shrugs, fingers pointing upwards like a Roman Roy gif,He has said before that it’s not his style to draw directly from his personal life and describes playing Benji as, “It’s just coming off my face or out of my mouth or whatever,”What he will say is that he finds it boring watching actors trying to feel feelings on set