The Kiwi will join Triple Eight's two-car Mercedes line-up for the second round of the Aussie GT season.
He will replace Broc Feeney in the #888 Mercedes partnering Prince Jefri Ibrahim.
It will mark Stanaway's second GT outing with T8 this year after joining the team for the Bathurst 12 Hour back in February.
Stanaway is part of T8's wider driver line-up, having signed on to partner Shane van Gisbergen for the Supercars endurance races later this year.
The other T8 Mercedes will be raced in Perth by Jamie Whincup and Prince Abu Bakar Ibrahim.
The two T8 AMGs are part of a 16-car entry for Perth which is headed by early points leaders Max Hofer and Liam Talbot in their Melbourne Performance Centre-run Audi.
Hofer isn't the only European import down under for the weekend with Chris Mies joining Geoff Emery in another MPC Audi.
Mercedes factory aligned driver Jordan Love also returns to GTWCA alongside Tony Bates.
The field also includes Bathurst 6 Hour winner Jayden Ojeda, who joins Mercedes squad Volante Rosso, while Renee Grace is another high-profile inclusion in her OnlyFans-backed Audi.
Practice kicks off at Carco.com.au Raceway with the points to be decided across two one-hour races on Saturday and Sunday.
