The last time Donald Trump met an Australian prime minister in 2018 he was named Malcolm.
On Friday afternoon local time in Buenos Aires, Scott Morrison met the United States president and took him through how he came to replace Mr Turnbull.
"They have their inquiries, and when you describe the parliamentary system, it's a foreign system to the presidential system," Mr Morrison told reporters after meeting with Mr Trump at the G20.
Mr Morrison said he took Mr Trump through the process of how Mr Turnbull was replaced and how he became prime minister in August.
"We just ran through what the events were," Mr Morrison said.
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Mr Turnbull visited the White House in February, posing for smiling pictures with Mr Trump and successfully pressing him to exempt Australian steel from tariff hikes.
