Donald Trump wanted help with the Mueller investigation. He saw a friend in Australia's Scott Morrison

Last month, as Washington dug into a July phone call between President Donald Trump and Ukrainian President Volodymyr Zelensky, Trump still made time for dinner.

A state dinner, to be exact. His guests of honor? Australian Prime Minister Scott Morrison and his wife, Jennifer.

Now, Morrison's government is one of several that finds itself embroiled in a growing political scandal out of Washington. The New York Times reported this week that in a recent phone call, Trump asked Morrison to help his administration investigate then-special counsel Robert Mueller's probe into alleged collusion between Russia and the Trump campaign during the 2016 election. The White House then limited access to the transcript of the call, the Times reported.

The Washington Post also reported that Attorney General William Barr has traveled abroad to meet with foreign intelligence officials as part of the Justice Department's inquiry into the Mueller probe and that requests for assistance were made to Australia.

Donald Trump and Scott Morrison at a State Dinner in the Rose Garden of the White House. Photo / AP

In response to the revelations, the Australian government said in a statement this week that it "has always been ready to assist and cooperate with efforts that help shed further light on the matters under investigation."

"The PM confirmed this readiness once again in conversation with the [American] President," the statement said.

The episode highlights what has become a particularly cozy relationship between Trump and Morrison - with the state dinner in Washington only the latest gesture that signaled the White House is prioritising a partnership with its ally down under.

In his toast to Morrison in the Rose Garden on September 20, Trump heaped praise on the Australian leader, drawing comparisons between Australia and the United States's national histories. He even quoted the late Australian poet Mary Gilmore - who just happens to have been Morrison's great-great aunt.

Then he raised his glass "to very special people and a very, very special country."

It was only the second time Trump has hosted a state dinner since taking over the presidency in January 2017. The first was an April 2018 meal with French President Emmanuel Macron and his wife, Brigitte (although some specialists take issue with last month's meal's classification as a state dinner, considering that as prime minister, Morrison is technically head of Australia's government, not its state).

But even if they have different titles, Morrison and Trump have latched onto the idea that they have a lot in common.

Like Trump, Morrison defied polls in Australia's last election. Like Trump, he made key allies in Australia's coal country on the campaign trail. And like Trump, he has made his hard-line views on immigration a focal point of his administration's policies.

Last month, Morrison attended a Trump rally in Ohio, where he acknowledged it's atypical for a foreign leader to get involved in local politics, but said "we do share a lot of the same views."

"We believe people should keep more of what they earn, we do think the best form of welfare is a job, we do think you can stimulate and ensure your small business entrepreneurs like we were seeing this morning," he said.

Australia has long been a close ally of the United States. And even as Trump has lashed out against a wide variety of US allies, he has kept his interactions with Morrison warm - a notable change from his relationship with Morrison's predecessor, Malcom Turnbull.

In 2017, just a week into his presidency, Trump spoke by phone with Turnbull, who was then prime minister, for what was supposed to be a routine, introductory call. Instead, Trump blasted him over an existing agreement that the United States would accept 1250 refugees from an Australian detention center, and told him that of all the talks he'd had with world leaders that day, "this was the worst call by far," The Post reported at the time. Then, 25 minutes into what was scheduled to be an hour-long conversation, Trump unexpectedly hung up.

Australian Prime Minister Scott Morrison and US President Donald Trump take the stage as they mark the opening of an Australian-owned plant in Ohio. Photo / AP

Morrison was elected the next year and defied expectations by holding onto power in a May vote, which Trump later called "a tremendous victory."

"He didn't surprise me, but he surprised a lot of other people," Trump said when the two met during the June G-20 summit in Osaka, Japan. "They called it an upset, but I don't call it an upset."

"It's a fantastic thing you did," he told Morrison.

Morrison quipped that Trump had a "warm invitation" to visit Melbourne for a golf tournament. When asked by a reporter if he saw how his "America First" policy could be interpreted by some allies, including Australia, as "America alone," Trump replied that Washington takes "care of our allies."

"And I think Australia is a good example," he said. "We've worked together very closely."