It seems the grand tradition of pieing is ??? ????? ????alive and well.

Qantas CEO, Alan Joyce, has had a pie shoved in his face by an unknown man at a business conference in Perth on Tuesday morning.

According to The West Australian, the head of the country's largest airline -- and one of the world's oldest -- was only three minutes into his speech at the West Business Leadership Matters conference, when a man in a suit came up behind him and calmly smacked a pie into his face.

The assailant slinked off to stage left, as Joyce stood there stunned, trying to clean the cream off his suit in front of 500 people.

However, Joyce maintained his composure, reportedly saying "I don't know what that was about," before stepping off stage momentarily to clean himself.

When he returned, he joked to the crowd: "Now, if there are any more pies, can you get it over with now?"

The unnamed attacker who looked to be in his 60s or 70s, was surrounded by security staff in the Hyatt Regency foyer. WA Police confirmed via email that a person is in custody in relation to an assault at a hotel.

While reports state the pie might have been lemon meringue, Joyce told reporters he didn't know what flavour the pie was.

"I don't even like pie," he said, according to a tweet by journalist Rebecca Johns.

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UPDATE: May 9, 2017, 1:51 p.m. AEST Added confirmation from WA Police.