"He gets on and he's being a bit rude. He was complaining about the plane and how close he had to sit to someone else," Trevis told the West Australian, as reported on by the Daily Mail.

"He started complaining about the seat and the quality, it wasn't what he was expecting."

Trevis claims Brand took his bag to the bathroom before exiting the plane while it was still on the runway.

"He was causing a bit of a scene. They [the flight attendants] weren't too happy with him, he was clearly being a bit rude," Trevis added.

Brand's alleged outburst comes after his decision to cancel a sold-out show of his Recovery Live! Tour in Perth due to coronavirus concerns.