Australia's former prime minister is one of several stand-in hosts for the daily CNN program Amanpour, whose host, the journalist Christiane Amanpour, is on leave.

Though Rudd is accustomed to a big stage, CNN International may be his biggest yet: the 24-hour global news network reaches a reported 200 million households around the world.

The show's format is issue, not news, driven, so to some extent Rudd was able to tackle topics in which he has a clear interest, and demonstrated expertise, specifically, concerns over China's economy and the challenges of climate change.

His guests included Chinese Vice-Finance Minister Zhu Guangyao, discussing the former, and Professor Lord Nicholas Stern, chairman of the Grantham Research Institute on Climate Change and the Environment at the London School of Economics, and Christiana Figueres, executive secretary of the UN Framework Convention on Climate Change, tackling the latter.

And perhaps because CNN's editing is infamously sharp, there were sadly no Ruddisms. At no point did he regale his guests with "fair shake of the sauce bottle", or one of his finest, "detailed programmatic specificity".

There was, however, a little room for personal touches; in discussing the extreme weather impact of climate change, Rudd revealed he had been trapped by the snowstorms on the US east coast earlier this year, and had to "dig his way out of a house."

He also talked about the importance of sport "to our various national psychologies." How important is it, he asked himself? (Note: rhetorical questions are pure Rudd.)

"Bucketloads," he said, in answer to his own question. "And most recently mainly bad; Australia's cricketers have been a in spot of bother."

On that topic, Rudd revealed he had been mocked by a UK customs and border official, as he arrived in London earlier in the day to film the Amanpour program.

"What do you call an Australian who's good with a bat?" the official asked him, when he saw the Australian coat of arms on Rudd's passport.

"Respecfully, I replied, I have no idea," Rudd said.

"A vet, of course," came the answer.

Rudd was non-plussed.

"There's only so much a former Australian prime minister can take," he deadpanned to the CNN audience.

Whether Rudd has a longer shelf life in the television journalism realm remains to be seen, but he possessed a certain stiffness of manner which is more consistent with talking to the press, not speaking as one of them.

In that sense, he's sharp, but he's no Leigh Sales.

The net effect is that an interview between, say, Rudd and Zhu Guangyao, comes across as a two government officials speaking off a script, and about a point on which both more or less agree, rather than the more typical cat-and-mouse game of a government official taking an official line, and a journalist attempting to deconstruct it.

An early press release from CNN said Rudd would also speak to former CNN International presenter Stan Grant about his Aboriginal heritage and the struggles Australia is still having coming to terms with its past, but that segment was not in the broadcast program.

Amanpour's other guests hosts include British Paralympian Tanni Grey-Thompson, human rights campaigner Trevor Phillips, political journalist Andrew Neil and historian Simon Schama.

In signing off, Rudd also spared CNN's international audience his traditional sign-off, "Gotta zip!".

It's a line he was famous for in Australian politics, generally delivered with the anxious urgency of Adam West's 1960s-era Batman, as though he was about to racing off and hop into the Batmobile, intent on putting a stop to Catwoman's latest shenanigans.

Instead, he took a more time-honoured approach to his sign-off.

"I'm Kevin Rudd, thank you for watching, and goodbye from London."