Ian Thorpe has become the face for the "yes" campaign in the same-sex marriage debate

One of Australia's most powerful chief executives, a former prime minister and a champion Olympian are all joining the same-sex marriage debate. And as Federal Government ministers publicly vent their disagreements over the issue, the Opposition Leader has also jumped in with his thoughts on those arguments. But, separately, the Labor leader has now had to fend off questions about his past as a dual citizen.

Ian Thorpe talks with gay-marriage supporters in Sydney Source: AAP