Former prime minister Malcolm Turnbull says Indonesian President Joko Widodo stands out as the most impressive world political figure he worked with, describing him as "one of the most important leaders of our time".
Mr Turnbull said the young president, who he has previously described as a close friend, was "very modern" and had a in an interview with SBS News.
"He is democratically elected and he stands for and embodies the proposition that Islam is compatible with moderation and democracy and that is his vision for Indonesia," the 65-year-old said.
"Indonesia is our closest neighbour, it is the largest Muslim majority country in the world. His success in standing for that moderate tolerant approach to an Islamic society or a society that is majority Muslim is critically important."
Mr Turnbull had a close working relationship with Mr Widodo during his prime ministership, once described by the as a "batik bromance".
In 2018, the Indonesian President, known as Jokowi, and his wife Iriana dined at the Turnbull's Point Piper mansion, with the then-prime minister posting a cosy selfie to Instagram after the meal.
And the friendship did not end with his ousting from Australia's top job in August 2018. Two months after he was removed from office, Mr Turnbull met with Mr Widodo at the request of current Prime Minister Scott Morrison in a last-ditch bid to repair relations between the two island nations.
"He [Mr Widodo] is a remarkable person and one of the most important leaders of our time," Mr Turnbull said.
The former prime minister was less glowing in his review of United States President Donald Trump, appearing to suggest he was a "lunatic".
"[Barack] Obama said very enigmatically ... don’t worry Malcolm the American people will never elect a lunatic to this office. But Trump was elected and lunatic or not we then had to deal with him," he said.
Mr Turnbull was promoting his new memoir, A Bigger Picture, which he said details some of the "stormy moments" of his relationship with Mr Trump.This includes the , in which Mr Trump furiously rejected a plan to take refugees held on Manus Island and Nauru hatched under former US President Barack Obama.
US President Donald Trump and Malcolm Turnbull during a press conference at the White House in 2018. Source: EPA
"When he was elected, I mean everyone knew what he was like, right? He was this mercurial, colourful, reality TV show host, flamboyant billionaire ... He was a star of the tabloid gossip columns in New York and a most unlikely person to be president of the United States," he said.
"Trump has governed as idiosyncratically, as erratically as he conducted his business before he became president. He is the most unconventional, unorthodox president America has ever had."
He added that Mr Trump was sometimes "very funny" and recalled constructive engagement on issues of trade between the US and Australia.