The project is the culmination of an ambitious project undertaken over the past 18 months. Since the NPG was established in 1998 more than 50 portraits have entered the collection through the commissioning program.

NPG director Angus Trumble said the project emphasised the gallery’s ongoing commitment to commissioning contemporary portraits, and the unique relationship between sitter and artist.

So how does this process work?

“The first step is always to secure the subject of a new portrait,” Trumble says.

“Not everyone agrees, some people feel modest and they feel they'd rather not for whatever reason, but most people are enthusiastic.”

For this project, he said, the gallery wanted a good geographical spread so the whole country was represented and a broad range from all walks of life.

“And different areas of achievement: business, sport, art, literature, poetry, dance, government, military, and a mix of gender and ethnic diversity.

“We could come up with 20 lists of 20, none of which overlap.”

Is a matchmaking of sort done between subject and artist?

“We look for what might be a productive sort of spark between artist and subject to the best of our knowledge, a spark that will produce something exciting.”

The gallery paired up rugby league legend Mal Meninga with rugby league tragic, artist Peter Hudson.

Trumble says he wasn’t aware Hudson had an interest in rugby league when they suggested he paint Meninga.

“Sometimes we’re lucky and there is a connection we didn’t even know about.”

All of my portraits are motivated by my own personal hero worship. I usually kind of selfishly choose who I want to paint and when the National Portrait Gallery asked me to have the great honour of being in this project and they suggested Mal Meninga, I was over the moon.

Mal is one of my heroes. I'm a passionate Queenslander and I love rugby league. Like every other Queenslander around State of Origin time, I turn pretty primal. It’s an interesting phenomenon.

We didn’t stop talking. Of course any league fan who has Mal Meninga captive for half a day is going to ask about all those great moments.

I went down to Canberra and spent half a day with Mal. It was the only way to do it. I didn't have the luxury of him coming to my studio here on the Sunshine Coast for a couple of months. So in Canberra we did some sketches and I took some photos of him.

I already had a preconceived idea of what I wanted to do with him so I took these preliminary visuals and brought it back and worked on the painting here.

The thing I needed most in that short period of time we had was to get as deep into the bones of Mal as I could. His personality and his generosity allowed me to do that.

I was so grateful. He let me get down underneath the skin and that’s kind of what you need for a portrait.

Whether I’m doing a landscape painting or a portrait, there has to be a sense of the spirit of the person or the place. I don't really know what that is but I know when it’s there. If it is there then that painting has a damn good chance of looking good.

Chris Chapman, the senior curator of the exhibition, was there initially and asked Mal the question of what it was he wanted me to bring out in the painting. Mal’s background has been pretty tough but he made it very clear that that wasn't his world. His world is very positive and his world was his family and football. He said he was a forward-looking positive person and he didn’t want to go into that past.

Mal is a gentleman, a very articulate, intelligent, warm kind of guy and we talked a lot about his style of coaching. I could see how young footballers would respond to Mal, not only the physical prowess but his mental and psychological awareness and what they can learn from that about their own responsibilities.

The thing with heroes, you kind of almost have a sense that you know the person, because you've watched them, you've seen them, you've seen them perform, seen them on television. It’s kind of a default sense that you know them and that somehow makes it a bit easier. Working with Mal went beyond all that.

Peter Hudson's exhibition 24 Hours Under a Dwarf Star opens at Harvey Galleries in Mosman, Sydney, on October 26. 

I enjoyed Peter’s company, he loves a bit of a yarn, loves his footy, and we had a good chat when he was in Canberra. He's a very talented man.

I’ve had a painting done before, for the centenary of Canberra, and photographer Heide Smith took a photograph back in 1991 which is also at the National Portrait Gallery. And then there’s the statue at Canberra Stadium.

I really haven’t done anything but play good footy. To get that recognition along the way is special and humbling because maybe you've had a positive impact on people along the way, playing football has allowed me to have a voice. Not everyone is a leader, but it’s about leaving a positive legacy, having a positive impact on the people around you and the causes you choose to help out with.

I loved the finished painting. It reminded me how old I was. There's this way you look at yourself, think about yourself, and when you see someone else's take, it really does make you think about where you are in life.

There was a lot of contemplation in the process. Peter and I were just talking about our lives when he was doing the sketches and taking the photographs, and I was rehashing my history and my past.

I'm at peace now, I'm pretty happy with my life and I can see that in the painting. If that is what it reflects, if that's what people get out of it, that’s a good thing.

He’s caught me in my natural stance too which I liked, in jeans and t-shirt with my hands in my pockets. I would have been wearing shorts and thongs and a singlet if I could have had my way.

How do I wanted to be remembered? Everyone wants to be remembered for being a good person first and foremost, respectful and kind, and to have made a positive impact on the people you meet in your life.

I wish I could paint, I wish I could sing, I wish I could do a lot of things but it turns out I could play footy pretty well and to think that’s what has got me to this point of my life isn’t a bad thing.

20/20: Celebrating twenty years with twenty new portrait commissions, will be on display to the public from 20 October until 10 February 2019.