Inner city MP Tanya Plibersek has decided to push for gay marriage in federal parliament and is backing Bill Shortens private members bill.
The ALP is suddenly all in favour of "equality" following the Irish referendum.
But it wasn't always this way.
A self proclaimed progressive, Plibersek has been in parliament since 1998, but it wasn't until two years ago that she finally supported gay marriage.
For well over a decade she refused to support the large gay population in her electorate who lobbied hard for an end to marriage discrimination.