TALK about fully sick! It pays to check your seat pocket on flights because you might find a priceless piece of art like this original drawing by American cult comic book artist Brian Stelfreeze.

Travelling to Sydney on a morning flight from Adelaide, where he was believed to have been visiting friends, Brian decided to use a sickness bag as a sketch pad, inking a drawing of Catwoman.

A photo of the illustration was posted to his official Twitter account with the words: “If you are flying from Adelaide to Sydney in Australia today, Brian left this hidden art for you to find. #stelfreeze.”

If you are flying from Adelaide to Sydney in Australia today, Brian left this hidden art for you to find. #stelfreeze pic.twitter.com/ATXLikmy8k — Brian Stelfreeze (@Stelfreeze) April 26, 2018

We’ve heard of “easter eggs” (hidden surprises) in movies and video games, but never on a commercial airline flight ...

The image is the Catwoman that Brian created for DC Comics’ Wednesday Comics.

Brian has painted more than 50 consecutive Batman: Shadow of the Bat covers for DC Comics and also works for Marvel, where he is the artist for the recent revival of Black Panther.