The Bamboo Engineering World Touring Car team has announced that American Robb Holland will race alongside regular 2012 driver Alex MacDowall at Sonoma this weekend.
Holland has competed in the Pirelli World Touring Car Challenge this season, and has also made six starts in the British Touring Car Championship behind the wheel of Tony Gilham Racing's Honda Civic.
Holland is the third driver in three rounds to race Bamboo's #12 Chevrolet Cruze.
WTCC rookie Pasquale di Sabatino was unable to drive in the preceding meeting in Brazil as he was recovering from bronchitis and pneumonia.
The single-seater convert was replaced at Curitiba by Scandinavian series frontrunner Michel Nykjaer.
Bamboo team principal Richard Coleman said: "It is never ideal for a driver to join a team in the middle of the season, but we will do our utmost to support Robb.
"Alex has demonstrated a lot of natural talent and done a very good job this year, but we know we are asking a lot of him to lead a team at 21 years old.
"We saw when Michel jumped in the car in Brazil he was less than two tenths off [factory Chevrolet driver] Rob Huff, so we know the car is quite competitive.
"At the moment, Robb is competing as a one-off. We'll have to see for the final three races, but we have had quite a lot of interest from enquiring drivers."