Brown, who replaced van Gisbergen at Triple Eight in Supercars, is set to make his NASCAR debut for Richard Childress Racing on June 9.
He will have a familiar face on his side, too, with van Gisbergen poised to take the secondary spotter role for Brown alongside a primary spotter.
The tie-up comes with the blessing of van Gisbergen’s contracted NASCAR team Trackhouse Racing.
Van Gisbergen will be competing at Sonoma that weekend, however only in the Xfinity Series with affiliate squad Kaulig Racing and not in the Cup Series race.
That will leave Brown and Cam Waters, who lines up with RFK Racing for a Cup Series debut of his own, as the down under drivers in the field.
Brown and Waters twice shared the Supercars podium in Perth last weekend, and discussed what it will be like making their NASCAR Cup Series debuts together.
Waters said: “Obviously I have done two [NASCAR] Truck races which has been a massive experience and a massive eye-opener.
“I was super pumped and then when I heard Will was doing it, I was just a little bit more excited again. They race pretty wild over there so hopefully we look after each other!”
Brown added: “Hopefully I can get more experiences and more knowledge and bring it back here as well — it’s pretty cool to do a NASCAR race.
“I started talking to Cam and he said he’s doing it as well and I thought ‘that will be pretty cool’. Hopefully we can have a good race over there and have a good time.”