Australian Prime Minister Malcolm Turnbull has said he wants to negotiate a "very strong" free trade agreement with the UK after it leaves the European Union.
Speaking at the G20 summit in the eastern Chinese city of Hangzhou on Monday, Mr Turnabll said Britain's decision to leave the EU was a "very momentous and historic choice" and Australia is "determined" to provide the UK with "all of the support and assistance that we can".
"We are such great friends, such strong allies - there's couldn't be two countries with closer bonds," he added.
Mr Turnball's comments will come as a welcome relief to Theresa May, following less-than-positive remarks made by other world leaders at the summit.
Japan's government issued a stark warning about the impact of Brexit on Japanese firms in the UK.
Meanwhile, President Obama warned that a trade deal with the UK was not top priority, but said the trading relationship between the US and the UK could become stronger following Britain's withdrawal from the EU.
Responding to Mr Turnball's remarks, Mrs May told the Australian leader: "I'm very clear (Brexit) doesn't mean we're going to be inward looking. In fact, we want to be even more outward looking around the whole of the world.
"Obviously Australia, with our long-standing ties and our close relationships, will be one of those countries we'll be looking to."