Former Prime Minister Kevin Rudd has mocked US president Donald Trump during his appearance on  The Project.

The segment, which discussed the political discourse between China and America, brought up the topic of Trump, as Rudd was asked for his opinion on the leader of the free world.

Guest host Magda Szubanski asked Rudd if the recent tweets made by Trump regarding China would have any impact on Australia.

“There’s a real danger we become roadkill or collateral damage in this,” said Rudd.

“It’s not just the trade war which is impacting badly on the global economy.”

Rudd then went on to discuss the President’s personal impact on the international tensions.

“Trump has a number of highly legitimate complaints against Chinese trade practices but I question his ability to seal the deal, to close the deal,” he said through a smile.

Which is when host Waleed Aly decided to offer a sarcastic quip of his own.

“But he wrote a book on  The Art Of The Deal  – how can you doubt him?”

“And it’s bulls***,” responded Rudd.

The comment left panel and audience members in stitches, making the former Prime Minister quickly realise his mistake.

Covering his mouth, Rudd said: “Sorry, it’s not … some other (word).”

“It’s okay we know you swear,” said Carrie Bickmore, with Peter Helliar adding “we’ve seen all the tapes.”

The comment was made in reference to a leaked video in 2012 showing Rudd becoming frustrated while attempting to record a message in Chinese.