Chasing after Tom Gleeson's Big Brass Mug this week are experts in Australian zoos, rap group Salt-N-Pepa, animated series BoJack Horseman, and a fascinator-wearing fan of ballet superstar Anna Pavlova.

It's a Battle of the Duds this week on Hard Quiz.

Returning are Katharina with her expert subject, penicillin; Matt with the Isle of Wight; Marcus, who's desperate to prove he knows something about dinosaurs; and Kate, who's ready to do backflips once more over Olympic gymnast Simone Biles.

Tom Gleeson is ready to take down four contestants foolish enough to have a second try at getting their hands on the Big Brass Mug.