As long rumoured, Kostecki will make his debut in the top NASCAR tier at the Verizon 200 on the Indianapolis road course on August 13.
He'll do so in a third Richard Childress Racing (RCR) entry backed by Peter Adderton's MobileX company. He will race alongside teammates Austin Dillon and two-time NASCAR Cup Series champion Kyle Busch.
RCR are the defending winners at Indianapolis, taking victory in 2022 with then-driver Tyler Reddick.
The deal comes as part of an alliance of sorts between Kostecki's Erebus team in Australia and RCR, Kostecki having been part of an Erebus delegation that visited the States earlier this year.
“I am thrilled to be making my NASCAR Cup debut at the Brickyard,” Kostecki said.
“It’s an honour to compete at such an iconic venue and against some of the biggest names in motorsport.
“I’m incredibly grateful to RCR for giving me this opportunity and I’m determined to make the most of it.”
Kostecki does have experience racing in the NASCAR system, having spent part of his childhood in the US and two seasons in the K&N Pro (now ARCA East) Series in 2013 and 2014.
In 16 career starts, he won two poles and had one top-five and four top-10 finishes. His career best finish of fifth came at Dover (Del.) Motor Speedway in 2014.
“Racing is at the core of everything I do, and NASCAR has been a lifelong goal of mine after spending years growing up in the sport's heartland in North Carolina," he said.
“It’s a whole different world over there and any additional time I can spend racing is only going to help me try and win my first Supercars championship.
“We got some great exposure to the inner sanctum of the team during our recent trip, and I cannot wait to immerse myself in the team, this time as a Cup Series driver.
“I can’t thank MobileX, Erebus, VAILO, Shaw & Partners, Southern Cross Truck Rentals and all my supporting partners enough for coming on board.”
Kostecki is currently fighting for a maiden Supercars title, sitting second in the standings, just seven points behind Erebus teammate Will Brown.
The NASCAR cameo isn't being seen as a distraction, though, with Erebus boss Barry Ryan welcoming the additional seat time.
“We have always encouraged Brodie’s pursuit of more racing opportunities,” Ryan said.
“Providing him with the chance to explore and excel in various racing disciplines not only enhances his skills but also contributes to the overall growth and success of our team.”
Fellow Supercars star Shane van Gisbergen made headlines earlier this month after winning on debut in NASCAR's first-ever race on the Chicago Street Course.
