The team has campaigned Lotus machinery in each of the last two Bathurst races, failing to finish on both occasions.
Former British Touring Car Champion Gordon Shedden will again spearhead the driver line-up, while the car will be sponsored by compareinsurance.com.au.
“We wanted to move up to Class A for this year and fight with the big boys in GT3,” said Motionsport team principal Simon Phillips.
“It's going to be so tough at the front, but the Aston is the weapon of choice and we've got some circuit knowledge. I can't wait.”
The Motionsport Aston joins the two Craft-Bamboo Vantages on the Bathurst grid.
“Gordon Shedden has been talking to us for some time now so we are really pleased he is finally behind the wheel of one of our cars,” said Aston Martin Racing team principal John Gaw.
“We are a global brand with drivers from around the world but we are also dedicated to supporting young British talent to race at the top level.
“The Liqui-Moly Bathurst 12 Hour is fast becoming one of the top GT3 races in the world and we are looking forward to seeing what the Motionsport team can do there.”
The Motionsport Aston brings the GT3 component of the Bathurst entry to 30 cars.