Brown, who was under contract with Erebus until the end of the 2024 Supercars season, recently emerged as the front-runner to replace van Gisbergen.
It was thought that Erebus majority owner Betty Klimenko had informally granted a release. That release has now been formalised with Brown's impending exit now confirmed by Erebus.
“Will has been a part of our team for almost six years and while we are disappointed to see him go, it will be business as usual for the remainder of 2023,” Erebus CEO Barry Ryan said.
“Our combined focus is on securing both titles and building Erebus to be the best team in pit lane.”
As flagged by Ryan, Brown has been aligned with Erebus since early in his junior racing career.
In 2019 the team committed to running him in a main game Supercars entry in 2021, despite still having two drivers – David Reynolds and Anton de Pasquale – under contract.
Both ended up leaving the team at the end of 2020, paving the way for Brown to step up alongside Brodie Kostecki.
Source: Autosport