Parenting has also been a revelation for Tim, who is a doting dad to four young sons – Roman, 10, Felix, 9, Wilfred, 6, and Otto, 2 – with his musician wife Rachel, 39.

The best-selling author talks to the Weekly about fatherhood, faith and why finding love in his late 40s was less challenging than enduring Donald Trump’s handshakes.

Is there something from your childhood you’ve intentionally tried to replicate with your sons?

Special one-on-one time. Each Friday after school, I’ll take one of the boys – we get a juice pack and some vege chips – and we’ll go somewhere to shoot the breeze. To be frank, it’s hardly the offer of a lifetime. My father, Warren, did that with me. He’d take me on a Friday to the Shalom, which was a coffee bar in New Plymouth, and we’d both have milkshakes. It was special. When you’re a parent, you can get caught up in the administration, so you have to create moments.

You were adopted at birth – why did you wait until your 30s to find your birth mother?

That was deliberate. I was always encouraged by my parents to do it, but I had seen other adopted kids in the phase of individuation – in their late teens and early 20s – seek out their birth parents for an identity. There can be a sense among adopted kids that you don’t have the same value. And I remember making a decision that I wanted to figure out who I was before I went to find her. This makes me sound wiser than I was at the time! At 33, I found my birth mother, who lives in New Jersey.

Did you see similarities in yourself?

Oh, yeah. It was said of her as a teenager that she could talk to a stick. I’m extroverted, I’m talkative, and we both have a quirky sense of humour. It’s been wonderful to meet her and get to know her. She made an immensely courageous decision at the age of 15. She’s the hero of my life. I can honestly say I’ve been loved into being by her, and my Mum and Dad. I know these stories don’t always work out well, but it’s certainly been great for me. I quite recently found my birth father through spitting into a DNA kit. Connecting with him has been really wonderful, too. A reminder of the power of genetics!

Did locating your birth mother in America play in your decision to move there?

Not really, I just wanted to get hired by the New Yorker magazine, but they weren’t hiring Kiwi schmucks. When I left for New York with no job to go to, I didn’t think I’d ever come back to New Zealand. Because growing up in Whanganui, we thought Palmy was like Paris!

During that time, you interviewed many US icons. Share some memories…

In 2008, I met the man who would be President. At the time, [Donald] Trump was the face of Lotto in New Zealand. “Win Lotto and have a Trump lifestyle!” When you meet him, he does the power handshake – he’s on the top, you’re on the bottom, and it goes on and on and on. But he’s a germophobe, so he slathers himself with antiseptic cream beforehand. He was also very charming, lots of fun and playful. Because we got along so well, I did call someone to get another soundbite out of him. But she goes, “No, Mr Trump did not like your story, he will not be talking to you again.” Celine Dion was also really funny.

Describe spending an afternoon with pop star Taylor Swift?

She was showing me the “T Party Room”, which is a thing she has for her fans. There are pictures of Taylor with stars everywhere. During the interview, I asked her, “Do you ever worry that one day you’ll wake up and discover you’ve turned into a raving ego maniac?” Her face just dropped. And she went, “No, because I worry about everything else. I worry about pyro going off in the show, I worry about the backing band, I worry whether I’ll ever write another hit song again.” To this day, I can’t tell you if she was actually showing me something true and vulnerable.

When did you know it was time to return to home soil?

I had this sort of fatigue. Like, if someone asked me if I wanted to go to dinner and mentioned Salman Rushdie would be there, I’d reply, “Oh, I can’t be bothered”. I’d been to events like that where everyone’s sitting around the table trying to be noticed by the person who’s the star of the show. I’d always wanted the bright lights, but once I saw what was behind them, I realised I was more of a Kiwi than I’d prepared to admit to myself.

After being raised by a Presbyterian minister, when did you lose your faith and find it again?

I lost my faith at university. I became detached from a moral code. I didn’t want to be good, I wanted to be naughty. But I didn’t really understand what that meant. So I became an atheist in my 20s – that’s exhausting – followed by a dreary agnostic. I succumbed to the cartoon that religious faith and an intellectual life are mutually exclusive, which is not true at all. Then in New York, every night after my 2am live crosses to TVNZ, I would drive past the front door to St Cecilia’s church, and all the homeless people would be on the front steps. It seemed to me like a place of refuge. And I had to admit that I needed a refuge. When I finally attended a Mass there, I found myself weeping uncontrollably – it was so beautiful. I was like, “I have to come back!”

Did you meet your wife at church?

Well, a mate and I went to midday Mass – “sad sack club” – at Auckland’s St Patrick’s Cathedral. And I remember turning to him and asking, “By the way, are there any…?” And he knew what I was going to say. He looked into the middle distance, shook his head and said, “Slim pickings around here”. But here’s the deal, I ended up meeting and marrying my darling Rachel there. We’ve since had four sons, and that mate married Rachel’s sister – they now have four daughters.

What’s the first thing Rachel said to you?

One Sunday, we were preparing to give a Bible reading, and I said, “Oh, I find I get quite nervous before I do this, how about you?” She looked at me deadpan and said, “It’s like walking to the slaughter”, and then turned away to keep talking to someone else. I thought, “That’s quite good!” I’ve actually written a poem about it. The line after goes: “Pretty girls don’t say such things and stay merely pretty.”

You’ve written three novels – do you have a favourite book?

In Search of Lost Time by Marcel Proust – a French novelist. I became quite fascinated by this guy because he had to self-publish the first volume and then it won the biggest literary prize in France. His brother Robert was a doctor who pioneered a prostate treatment that was nicknamed the “proustatectomie”.

And what are you currently reading?

I’m currently enjoying Elizabeth Gaskell’s Cranford as part of our Maxim Institute book club. It’s narrated through a distinctly female perspective. I read a lot of women’s fiction to gain fresh insights, and Cranford really delivers.

Sum up raising four boys?

A circus! But it’s the best circus we’ll ever be the ringleaders of. Before I met Rachel, I thought, “Well, I’ll probably just be someone’s uncle. That’s as good as it’ll get”. Now to have four filthy Philistines – nah, they’re really lovely boys – inside my heart is such an abundance. I’m not as young as other fathers, but I think I keep up.

How do you plan to celebrate your 60th birthday in October?

We’re taking a once-in-a-lifetime family cruise that’s also coincidentally (not) a birthday celebration for other loved ones.