Joyce, who was the keynote speaker at the leadership event hosted at a Hyatt Hotel in Perth, had just begun to address the audience when a man dressed in a suit approached him from behind and pushed the pie into Joyce's face.
The incident was captured on camera.
The man who pied Joyce was apprehended by security and held in a room until policed arrive, according to a report from the Australia's 7 News. Police then took the assailant, who has not been identified, to the police station for more questioning, according to the report. It's unclear what the man's motives were.
Joyce excused himself from the stage after the incident to clean up, but then returned back to finish his presentation.
Joyce even joked with the audience after returning to the stage.
"If there are any more pies, can you please get them out of the way now?" he said.
After the event, Joyce spoke with media and said that as the CEO of an airline company he has learned to expect the unexpected.
"When you've been the CEO at 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," Joyce told media after the event.
You can watch the whole incident below: