The Perth-born 21-year-old with a Welsh grandfather flirted with an international career for Wales after being overlooked for Socceroos selection but was convinced to join the fold after a visit from Verbeek last year.

"I think it was always in my heart and in my mind that Australia would be my country and I'm so glad to be in the 30-man squad to be in the World Cup," Williams said in a televised interview after being named in the preliminary Socceroos lineup on Tuesday.

Williams, who was also eligible to play for India and England with parents born in Mumbai and Kent respectively, was rewarded with his Socceroos' debut against Japan in their final World Cup qualifier last year. He has since nailed down a starting spot at Middlesbrough after starring for Burnley during a loan stint and will compete for the right to play alongside Socceroos stalwarts Lucas Neill and Craig Moore in defence.

"It's going to be tough to get in the final 23 but if I work hard and show what I can do, I think I might be a chance," said Williams, who has been capped three times. A tough, versatile defender who can also conjure a spectacular goal, Williams is upbeat about the Socceroos' chances.