Samuel will announce the winner of the short film festival's Public Vote Award when he joins a host of other celebrities at the event on Sunday.
Celebrity judges already announced are actor David Wenham, actress Kat Stewart, Joel and Nash Edgerton and Animal Kingdom writer and director David Michod.
The Optus One80project gives aspiring film and TV makers a chance to turn their idea into a shot at the small screen.
As well as the public vote, awards will be handed out for the judges' choice and best student entry, with the judges' pick to be made into a one-hour drama for broadcast on MTV
The event, to be held at Sydney's Prince Alfred Park, will be hosted by comedian Tim Ross and MTV personality Daisy McKenzie-McHarg.