Just as it was in Singapore, in New Zealand Williams' tattoo will be covered by his costumes - first an outfit befitting a "17, going on 18" Austrian boy, then Hitler Youth regalia. When asked if it's difficult to act out such a poisonous part of history, Williams concedes "the costume helps with the journey".
Williams, 29, loves his rugby. Naturally he's a Springbok fan but he also avidly follows the Waikato Chiefs, despite this being his first visit to New Zealand. He used to play fly half for Nelson Mandela Metropolis University in Port Elizabeth before he tore a knee ligament, a similar injury to afflict Kiwi Nick Afoa, now starring as Simba in The Lion King in Australia.
Just like Afoa, Williams finds the athleticism of his rugby background helps with the fitness required to perform on stage. Williams' rundown of his rugby pedigree and mention of his hometown earn a good-natured dig from cast mate Bethany Dickson from Cape Town; "Port Elizabeth, the armpit of South Africa."
Dickson, 26, plays the lead role of Maria, a part first made famous by Mary Martin when The Sound of Music debuted on Broadway in 1959. The story of the singing Von Trapp family was then immortalised on film in the 1965 movie starring Julie Andrews and Christopher Plummer.
Even though Dickson's Maria and Williams' Rolf are not closely connected on stage, the two are bound by more than a shared nationhood and musical talent - they're first cousins. Their mothers are sisters, and Dickson's mother Julie is also a performer. She starred as Maria in The Sound of Music in South Africa 12 years ago, when Dickson played one of the Von Trapp daughters.
Dickson and Williams' grandfather was a well-known figure in South African rugby circles. Williams says he "watched a lot of the Springboks" with him and mentions photos of him dancing with Dickson when she was little. Although the two stage stars were brought up in different cities, they spent a lot of time together when they were growing up.
They're spending even more time together now. The production kicked off in Cape Town and Johannesburg in January, opened in Singapore last month and after its New Zealand season will head to China and Hong Kong. The cast and crew are largely South African, apart from the children who play the youngest six Von Trapp offspring.
The children's roles are cast in each city in which the show is based. In New Zealand, 18 Wellington and Auckland children will play the Von Trapps, with three children alternating each role. The New Zealand cast was announced in late June after an exhaustive audition process in May. More than 1000 children were put through their paces - dancing, singing and acting for the show's resident director, Anton Luitingh.
Luitingh was thrilled with the response. "The more you have [auditioning], the more you get what you want," he says, noting girls from the recent New Zealand production of Annie are in The Sound of Music.
Amelia Walshe, who played Annie, stars as Marta, and Bronte Walshe and Venice Harris, who both played orphan Mollie in Annie, will alternate as Gretl.
Luitingh says the timing auditioning children for the roles has to be impeccable - three to four months ahead at most. "You can't go too early. Kids grow up, especially the boys, whose voices break." The Kiwi kids started rehearsing recently, training fulltime, six days a week to be ready to shine on stage.
"It's pretty hectic," says Luitingh. "It's a balance between being too rigid and disciplined and letting them have fun. It's a bunch of kids on stage with their own personalities."
The young ones have worked hard to get where they are. Even the best singers, actors and dancers aren't shoo-ins. "It's a tough ask. They've got to be able to sing, dance, act, be a certain height and be the right gender. We're asking the world of these kids," Luitingh says.
When the children appear in character, it's essential they stand in a "ski slope" line of ascending height - from little Gretl up to eldest brother, Friedrich. They must also have an X factor, a presence on stage and not be too introverted. "With [youngest character] Gretl you also need the cute factor as she steals the show nine times out of 10."
The oldest Von Trapp, "16, going on 17" Liesl, is played by 24-year-old Carmen Pretorius. Pretorius has been a professional performer since she was 18. She loves her job and the travelling, despite having to leave her chartered accountant boyfriend of six years behind in South Africa. Playing a teenager isn't too much of a stretch. "Costumes and makeup help a lot.
I find my inner child," she jokes.
Pretorius started singing lessons at 9.
"My parents thought it was a phase but it never left me."
Pretorius reiterates what all her colleagues have said, that the magic of The Sound of Music is thanks to the children - and the show's timeless themes. "It's important that people know that although it's a classical musical, it's valid and relevant.
"It's interesting for everybody and if you see any musical, it should be The Sound of Music. It's uplifting seeing the children perform - it makes you believe in the ability of the human race."
• Find out more at soundofmusic.co.nz.
