The dress was actually her mother, Sarie Kessler’s own 30-year-old wedding gown, with a few modern-updates thanks to Aussie designer Casey Tanswell.
"[Tanswell] had been approached by a friend to do the alterations," a source tells The Courier Mail. "She didn't know it was Margot until she turned up at her home for the fitting."
“She didn’t know it was Margot until she turned up at her home for the fitting.”
Margot’s mother also reportedly walked her daughter down the aisle at the ceremony and gave her away as she exchanged vows in the ultra-private ceremony at Harvest in Newrybar.
Margot and Tom met in 2013 on the set of Suite Française where Tom worked as an assistant director.
"I was the ultimate single gal. The idea of relationships made me want to vomit," she said. "And then this crept up on me," she told US Vogue back in May.
"We were friends for so long," she said. "I was always in love with him, but I thought, 'Oh, he would never love me back. Don't make it weird, Margot. Don't be stupid and tell him that you like him.' And then it happened, and I was like, 'Of course we're together. This makes so much sense, the way nothing has ever made sense before.'"