The line-ups have been finalised for three of the six factory-backed Audis that will run under the Melbourne Performance Centre banner at the round-the-clock enduro.
Mostert will team up with Liam Talbot and Fraser Ross in the CoinSpot-backed R8, which Talbot and Mostert took to victory in the opening race of the GT World Challenge Australia season at Phillip Island earlier this year.
That car will be overseen by Mostert's Walkinshaw Andretti United engineer Adam De Borre.
"It’s exciting and I feel like it’s our best shot at winning the event this year," said Ross.
“Chaz and Liam had a great round at Phillip Island in the new-specification car, and I got some laps at Albert Park so we’re very confident with the package.
“It’s the best possible team to go to the Mountain with. I don’t think I’ve ever been more excited to get to the track given we have a real opportunity to challenge for a Bathurst 12 Hour victory.
“The Audi team are the best around, and drawing Chaz and Adam to the team is proof of that."
Holdsworth, meanwhile, will join Marc Cini in the #9 R8 along with experienced Supercars co-driver Dean Fiore.
Brothers James and Theo Koundouris will race the #47 R8 joined by Bathurst 1000 podium finisher David Russell and experienced GT racer Paul Stokell.
The line-ups for the remaining three entries will be announced later this week.
“The first half of our 2022 Bathurst 12 Hour squad is fantastic," said MPC boss Troy Russell.
“The shift to the Pro-Am regulations this year gives opportunities to people who might not have the chance in ‘usual’ years and they have all grabbed it.
“Each car has a really strong group of drivers, both from the Am component and to the professional drivers who have joined in.
"These are three strong, very balanced cars all of whom can compete for a strong result.”
The Bathurst 12 Hour will take place on May 13-15.