Take a look at the moment it happened here:
The Qantas CEO at first appeared stunned by the incident but quickly regained his composure, telling the audience he did not know why he had been targeted before leaving the stage to clean up.
He then returned to continue his speech without his blazer, joking about the incident. "Now, if there are any more pies can you get it over with now?" he said.
Talking to reporters later, Mr Joyce joked he had been unable to identify what flavour pie he had been hit with.
"I have absolutely no idea - I'm not a big pie eater," he said. "I didn't have a chance to test it, it was mostly on my glasses."
"I think my issue is I need a new drycleaner before I leave Perth, so if you have one could you please recommend it to me," he laughed.
That didn't stop Twitter speculating:
Going sugar free this month has me jealous of Alan Joyce. What pie would I like to be pied with? Banoffee or Lemon Meringue I think.— Emma Pedler (@EmmaPeds) May 9, 2017
All flights on #Qantas this week come with a free Meringue Pie - Alan Joyce said they are delicious— Ciaran O'Donnell (@JustCiaran) May 9, 2017
@G_Parker Confident it's not lemon meringue. Too crusty on top for satisfying smearage.— Rebecca Leask (@MissBeck) May 9, 2017
Qantas boss cops a pie in the face from some old guy. Of the classic cream variety, I presume.https://t.co/sb5dFzO6oQ— Patrick Commins (@ComminsP) May 9, 2017
The unidentified man's motive was unclear but he was soon apprehended by security guards. State police later confirmed that officers had been called to an assault at a Perth hotel and that one person was in custody.
Long a slapstick comedy favourite, the pie-in-the-face routine has also developed as a form of political protest.
News Corp boss Rupert Murdoch was famously hit in the face with a pie while he testified before a British parliamentary inquiry into a phone-hacking scandal in 2011.
(With inputs from Reuters)
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