Alpine will supply the engines if Andretti Cadillac win their battle to become Formula One's 11th team, the Renault-owned sportscar maker's chief executive Laurent Rossi said on Thursday.
The governing FIA this month formally started a process that could lead to new entrants from 2025.
Andretti Global and General Motors announced in January they planned to compete with a new all-American team using the Cadillac brand and employing at least one U.S. driver.
"We agreed that if they get their licence to run in Formula One, then we will provide them with a powertrain," Rossi told Reuters at the launch in London of Alpine's A523 Formula One car.
"But it's up to them to show that they can join the Formula One circus and for that they need to go through the hoops, the process in place where they submit applications and they show that they bring value to the F1 circus and teams in general.
"It's for them to prove it and for the others to assess. If they join, we'll be happy to join them. If they don't it means that all in all it didn't work out."
Alpine, fourth in the constructors' championship least season, currently supply only their own team, and Rossi said the carmaker did not need a second.
"It's a nice to have, it's not a must have," he explained.
"We could use a second team because you accumulate more data across four cars than you do with two. But it's a drag on your team as well, so you need to be completely well structured. We couldn't that two years ago."
Mercedes currently supply four of the teams, Ferrari three.
Other Formula One teams have been lukewarm towards expanding the grid, wary of diluting the overall pot of revenues.
Some also feel the current $200 million entry fee, which would be shared among the existing 10 teams as compensation, is not enough.
Andretti labelling team owners as "greedy" did not sit well either.
While FIA President Mohammed Ben Sulayem has been supportive, Formula One chief executive Stefano Domenicali has sounded much less so.
"Michael Andretti is very vocal about joining F1. In my view it was not smart to say that the teams were 'too greedy' and protecting themselves," Domenicali told Sky Sports television recently.
The deadline for submission of formal applications to the FIA is the end of April with any decision by June 30.