Doohan and Brown are among a second wave of confirmations for the one-off celebrity race, which will take place on Mount Panorama on May 18.
Dakar winner Toby Price is also on-board, as well as DJR Team Penske's Ryan Story – one of four team bosses along with Brown, Barry Ryan and Brad Jones – motocross riders Dan Reardon and Blake Williams and former Australian Rally Champion Scott Pedder.
AFL player Jarmen Impey, Brisbane Roar defender Daniel Bowles and All Black Angus Ta’avao round out the latest confirmations.
In other Supercars Eseries news, Austin Cindric, Craig Lowndes and Will Power have been confirmed as wildcards for this week's races at the Circuit of the Americas.
, joining regulars Shane van Gisbergen and Jamie Whincup, and fellow enduro driver Garth Tander.
“My experience on a simulator is pretty limited, I missed that phase,” Lowndes said.
“I’ve used a sim in the past in my last few years of full-time driving, but it's just a different world.
“To get your head around not having that tactile feel of what the car is doing underneath you, is really something you’ve got to just change your whole focus.
“It’s been interesting to watch it from afar; it’s been quite humorous at times.
“If there’s only one driver I beat on Wednesday it's probably my teammate, Jamie Whincup.”
DJR Team Penske will have four representatives as well, Scott McLaughlin and Fabian Coulthard to be joined by a returning Power, and Eseries debutant Cindric.
, with Josh Fife taking the dedicated Super2 slot in the six-strong fleet of wildcards.