You’re in a new TV show called The Killings at Parrish Station, playing a detective who is plagued by an unsolved mystery. What do you think is life’s greatest mystery?

I don’t want to say anything too obvious, like death, but it is such a mystery. It’s hard not to sound like a cliche, [but] the greatest mystery is: how does it all end?

Speaking of death, and it’s a bit morbid, but what song would you like played at your funeral?

Oh, that’s not morbid. My dear friend James Valentine died recently, through voluntary assisted dying; knowing his family so well, joy is the word that kept coming up, so I do not find the idea of death morbid.

But the music I’d like? Oh, far out, I have thought about this, but I’ve never really come to a … I am drawn to songs that my sons love rather than what I love, and one son loves Teeks, the Māori singer. But my father used to play the steel guitar and sing American folk songs; I’ve got a recording of one of his. I’d like that played, I think.

You’ve just finished touring RBG: Of Many, One, in which you play not only Ruth Bader Ginsburg but three US presidents – along with 29 other characters. Which president did you enjoy being the most?

I certainly got the biggest audience reaction for Trump, but I must say I really enjoyed Clinton. Because of the way Suzie [Miller]’s written it, there’s humour in his conversation and that southern drawl. It’s a lot of fun, and I suppose it’s the longest scene I’ve got with any of the presidents; Clinton and Ruth are sort of getting to know each other before she’s chosen to be on the court. Also, people react so much to what they believe his relationship with Hillary was all about.

Is it true you found yourself brushing your teeth like Ruth?

In the first season, yes, but not any more. We’ve done more than 300 shows, and in the first season I found it very hard to stop speaking like Ruth, because I was still trying to get the language and the voices, so even in my non-theatrical hours I was practising her movements. I found myself driving like an old lady, for example, but I am now completely able to switch her off.

You met your husband, Martin McGrath, shortly after a seeing a tarot reader, who told you you’d meet a man. Have you returned to a tarot reader since?

Yes, in fact, because of that. Once our relationship began and we were definitely going to be together, I said, “let’s go and see someone, it was really fun”. We went to a woman in Melbourne, who had turquoise eyeshadow on. She was scary, and I’ll never forget it. She did Martin first and said all these amazing things about him – and I was kicking him under the table, going, See? Isn’t this great?

Then she turned to me and said, “Why don’t you go out for a walk, Martin, I’ll talk to Heather now.” She put her arm around me and said, “There’s not much to her, is there?” and then said to Martin, “Never mind, where did she go wrong?” I just panicked and looked at him, like Don’t leave me, don’t leave me.

He did go for a walk, and she said one terrible thing after another – telling me that I was going to ruin his life – and, anyway, that was my last time.

You made your professional acting debut aged 22 in Sydney Theatre Company’s production of Henry IV, Part 1. What’s the most overrated Shakespeare play?

Oh, I don’t know if any of them are overrated. I mean, I think the ones which are usually held in the greatest esteem, or seen the most and produced the most, are pretty magnificent plays – the Scottish play, Hamlet. Overrated? I mean, this will be controversial: I’m not as crazy about Twelfth Night.

If you could be any animal, what would it be?

I’ve always identified with a giraffe. That long neck, their head being so far and small compared to their body; it’s hard for them to get down on the ground, but they can. They seem to overcome their extraordinary physical challenge in order to reach the high leaves and yet still be able to get down. I just find something about giraffes so magical and wonderful.

Are you still making toast art for your co-stars and is there a superior bread for your canvas?

Yes I am. I did 65 toasts of every crew member on a show called Dalliance, that I’ve just co-produced and will be coming out later in the year through Paramount. I stayed up all night for a week [to complete them].

I won’t mention the label, but the whitest, most sugary, oldest fashioned bread is excellent for a portrait because you don’t want to get too many pockmarks – you don’t want raisins in it, for instance. But for a landscape, I love nothing more than a rough sourdough.

A Vegemite gallery in Victoria asked if I could do some Vegemite on toast for their gallery, and that was a lovely reaction. I’m hoping some bread company just offers me free bread!

What film do you always return to, and why?

I return to films that are sometimes connected to my childhood, or are the first films I’ve seen – things like It’s a Wonderful Life, which we watch at Christmas. Citizen Kane.

We watched Muriel’s Wedding again recently, which I had forgotten what an amazing film that is – how wonderful and joyous and fabulous.

Hugo Weaving is a friend of yours, but also your most notable on-screen lover, in the recent Love Me and in the 1984 series Bodyline. What’s Hugo’s most annoying habit as a co-star?

Oh darling, as if he has one! He’s so nice to everyone. He’s so lovely to the crew, so lovely to everybody. He’s annoyingly nice. He’s annoyingly lovely, which is why he’s so beautiful to work with too. He’s just annoyingly pleasant and present and lovely. He’s such a wonderful actor, but he’s such a wonderful person. It’s almost annoying how fabulous he is.

• Heather Mitchell appears in The Killings at Parrish Station, which premieres on Stan on 24 June