From a talking horse to the Dark Knight: Will Arnett ranks his own roles

Mr Perkins runs the bank that finances all the big crime sprees. Every time he talks about money – which is a lot – I wanted him to sound as if he wants to eat the money, like he is whetting his own appetite for money so much that he is salivating. When I put dog food in my dog’s bowl, she drools until she can start eating. I wanted Mr Perkins to do that at the very mention of money, and I stuck to it for the whole film.

The director, Barry Sonnenfeld, called and said: “Listen, I have this odd request. It’s just one really one long scene and you’re going to play a character who is Will Smith’s partner in a different dimension, but he doesn’t know who the fuck you are.” And I said: “Terrific.” I only had to show up for one day. Will Smith was incredibly welcoming, generous and hilarious. At the end of my scene, I smack him on the butt and walk away. Not a lot of people can say that they smacked Will Smith on the butt, but I can.

It was such an honour to be asked to appear on Sesame Street that I would have paid them. I got to do it with Elmo and Big Bird, and the episode still gets shown. I know, because when it does, people reach out on social media, which always makes me smile. I play a magician on the back of playing GOB on Arrested Development. They wanted to recreate it in more of a kid-friendly way. I had been asked to play a magician before, but I had always declined. This seemed like a really good exception to make.

When I was offered this role, I remember thinking: “What a terrible name for a guy in an action movie. l’m definitely going to be the guy who dies first.” Filming was interesting. It was hard to remember that you were supposed to be talking to these huge turtles because they were just actors wearing motion-capture suits with ping-pong balls stuck to their heads.

I am in awe at the comedy talent of Tina Fey. I was asked to play this character who is at odds with Jack Donaghy, Alec Baldwin’s studio executive. I was thrown at the mercy of such a great show full of characters. When we first meet Devon, he has so many ulterior motives. I loved the fact that the one thing Donaghy fears the most is that Devon is even more ambitious than himself. I thought that was a brilliant notion. There are very few people who can do what Baldwin does; he’s such an incredibly gifted, dramatic and comedic actor, and he really brings all of that together in 30 Rock.

I said yes before David Cross even asked me. I relished the thought of playing such a foul-mouthed and self-centred character alongside Cross (my co-star in Arrested Development) and Spike Jonze. The ruder Brent got, the more Spike would crack up, and I would crack up, too. I loved that Brent turns out not be be what he appears; he is actually a very insecure and demure guy. In one scene, he mistakenly thinks an old woman is another character in disguise. She was played by this very proper, older English actress, Rita Davies. During filming, I said to her: “I’m very sorry, but in the scene I have to pretend that I’m reaching down to grab you by what I think are going to be your testicles.”

When Brad Bird asked me to play Horst, I really didn’t know what he had in store. I turned up on the first day, and Brad went, “OK, so he’s German. Let’s start recording.” I immediately went into a hot sweat. I thought: “I can’t do a German accent. What am I going to do?” I mean, Karl Horst is very German. He talks about how he killed a man with his thumb. In the pressure of the moment, I thought: “What if I do a bar-trick German accent that everyone does?” So I just had to kind of lean into it. I didn’t have a lot of experience in voice acting, so I was constantly thinking: “Shit, am I going to be able to pull this off?” But it was a really amazing experience. Any time anybody tells me that they like Ratatouille, it puts a wonderfully warm feeling in my heart.

When I read the pilot, I thought it was hilarious. I don’t think anyone could have anticipated the journey that the show’s creator, Raphael Bob-Waksberg, would take us on. I was very much at the mercy of the incredible writing. He took BoJack to these great heights with such simplistic, emotional and spiritual depth. I didn’t anticipate it would affect me so much – after all, it is just an animated show about a talking horse. A lot of cynics would say: “Who gives a shit?” But the writing is so strong, it affects you in ways you weren’t expecting. Even though we have stopped making episodes, BoJack still feels very alive and very present.

On the surface, GOB seems like a run-of-the mill asshole. But he is really a guy who has been stunted emotionally and cognitively, because he has been so rejected by both his parents. He is barely tethered to the real world, and his coping mechanism is to create a persona in a world in which he is the star. For all his damage, GOB is an incredible optimist. He rarely suffers any self-doubt. If anything doesn’t work out, it is generally somebody else’s fault. I love that about GOB, that he uses his optimism to survive. I think what makes him relatable is those moments when he lets his guard down and you can see how damaged he is. I am sure there is a little bit of me in all my characters. I didn’t suffer from the same sort of emotional stunting as GOB, but I did start playing GOB when I was 33, at a point when my career wasn’t exactly taking off. I think I probably applied my own frustrations about my own place in the world.

I have never ranked my own roles before, but it feels right to place these three films at No 1. I did not realise what an impact Batman was going to have on my life. The character comes loaded with a bunch of preconceived notions, because he is Batman. He is a superhero with no super powers, so he has got to be quite confident. He’s an orphan and an only child, with incredible financial resources to do whatever he wants, and that has got to make him quite selfish. I liked the idea that he does not know how to be part of a team. It was fun taking things further in The Lego Batman Movie, to really get into what drove him. You know, witnessing his parents’ murder, being raised in this incredible mansion, and becoming this night-stalking vigilante who saves the world from terrible criminals, but then comes home and eats a heated-up dinner on his own. What does that do to you? I definitely drop into a lower register when I am cross with my kids. It is much more effective than raising my voice just to get [does Lego Batman impression] a little quieter and a little deeper. Batman is a character whom a lot of people take really seriously. We had a bunch of different stories that never actually ended up coming out, such as the idea that Batman was secretly Canadian.

The First Team is on BBC Two from Thursday 28 May at 9:30pm. The full box set will be available on BBC iPlayer after the first episode