Dean Fiore will contest the opening two rounds of the 2019 Dunlop Super2 Series with Eggleston Motorsport.
Fiore joins the Holden squad for next week's Adelaide opener and his home event at Barbagallo Raceway, where he finished on the round podium in 2018.
He accompanies Will Brown in the line-up, with a third driver to be announced 'in the coming days'.
Fiore contested the full Super2 Series for the first time in 2018 with MW Motorsport, finishing seventh in a Nissan Altima including winning the Bathurst 250km race.
The West Australian tested an Eggleston Commodore at Winton last week, before a deal came together.
"I’m very excited to be joining EMS for the opening two rounds of the 2019 season," he said.
"Ben and Rachael [Eggleston] run a very slick operation and I am really looking forward to working with them."
Fiore will drive the Triple Eight-built chassis raced by Brown for the last two years, but renumbered to #54.
Brown, who carries #38, steps into the sister car used by Nathan Morcom in 2017 and '18.
"While Dean is new to our team, he fit in instantly at the test day and got along with everyone really well," Rachael Eggleston said.
"He comes into Adelaide prepared and comfortable in the car and we cant wait to see what he can do.
"He will be an asset to our team on many levels and we are really looking forward to working with him to get the EMS cars on the podium next weekend."
The team's long-serving driver and 2014 title winner Paul Dumbrell steps back from Supercars driving in 2019.
2019 Dunlop Super2 Series Adelaide field so far
Brad Jones Racing: Jack Smith
Eggleston Motorsport: Will Brown, Dean Fiore
Garry Rogers Motorsport: Mason Barbera, Dylan O'Keeffe
Image Racing: Jordan Boys, Adam Marjoram
Kostecki Brothers Racing: Brodie Kostecki, Jake Kostecki
Matt Chahda Motorsport: Matt Chahda
Matt Stone Racing: Joel Heinrich, Ash Walsh
MW Motorsport: Tyler Everingham, Bryce Fullwood, Zane Goddard
Tickford Racing: Thomas Randle
Triple Eight: Brenton Grove, Kurt Kostecki