The campaign was launched over the weekend by Kylie Minogue’s fiancé Jonathan Sasse.
"I was shocked to find out earlier this year that same-sex marriage in Australia isstill illegal," the British actor wrote on the campaign’s website. "There are many hurdles to jump in order to make constitutional change, but we are now the closest we’ve ever been to that change."
"Let’s raise our voice and public support for change. Get a shirt. Wear your heart on your sleeve."
The shirt wasn’t the only bold look Margot sported for occasion, also donning a marijuana leaf dress by Alexander Wang.
Variety reports that according to Neilson data, the show, which also featured musical act The Weeknd, was SNL’s most-watched premiere in eight years.