If you're going to get a pie shoved in your face, you don't expect it to come from a stoic-looking, late middle-aged man in a suit. 

That was just one of the unusual details of a strange occurrence at a business conference in Perth, Australia, on Tuesday morning, as a speech by Qantas Airways CEO Alan Joyce was rudely interrupted with a dessert-based assault on stage.

Joyce, who originally hails from Dublin, was the keynote speaker at the West Business Leadership Matters event in the Hyatt Regency Hotel and was a mere three minutes into his address before an unidentified man approached him, grabbed him, and pushed a pie forcefully into his face before making a swift but calm exit.

The Qantas boss was quick to regain his composure after uttering an understandable expletive, telling the crowd of 500:

"I don’t know what that was about. Excuse me, I might take a break for a second guys and just clean up a little bit, then I'll come back."

Joyce dutifully did, completing his talk with lighthearted references to what had just transpired.

"Believe it or not, I was also voted the number CEO people wanted to work for in Australia," he revealed at one point, now sans jacket. "You wouldn't know from that pie in the face!"

He received a standing ovation at the end of the presentation.

The pie-bearer sat calmly in the hotel foyer following the incident, and was interviewed by police before subsequently being taken away in custody.

A 67-year-old man from Willetton in Perth has since been charged with giving a false name to police in relation to the incident.

Declining to discuss what possible motive the man could have had, saying that it was a matter for  the police, Joyce later stated:

"I think when you've been a CEO of an airline for nine years, there's a lot of things that happen over that period of time... This is different, but it's not unusual." 

As for what was in the pie?

"I didn’t have a chance to test it, it was mostly on my glasses.

"I think my issue is I’ll need a good dry cleaner in Perth, so if you have one please recommend one!”

The 50-year-old Irishman appeared on Newstalk's Down to Business in 2016, sitting in Bobby Kerr's executive chair to chart his journey from a working class upbringing in Tallaght to the head of one of the world's most famous airlines.

"When you get jet kerosene in your nostrils," he said at the time, "you get very fixated with the business."

The openly-gay chief executive also took the opportunity to praised Ireland's 'Yes' vote in the same-sex marriage referendum and called on Australia to follow suit, saying:

"It's a pity that Australia is so far behind the rest of the world."

Replay the full interview below.