The MG car, formerly built at the Rover plant in Longbridge in Birmingham, is to be built at a new factory in the US.
MG Rover's new owners are making an announcement on Monday
MG Rover's new owner, Nanjing Automobile, has said it plans to build a new assembly plant in Oklahoma.
It is issuing an announcement next week about plans for car production at the former Rover site, which closed when the firm collapsed last year.
Trade unions have expressed concern at the US news and are calling for talks while the city council has welcomed it.
Dave Osbourne, national secretary for the Transport and General Workers' Union, said: "There has been no consultation with us about this.
"There has been no consultation about Nanjing revising its plans downwards in respect of Longbridge.
"Taking these together, the T&G is calling for an urgent meeting with the company to find out exactly what they are now planning for car making in the UK."
The Okalahoma and Longbridge operations are part of a global business strategy by the newly-formed MG Motors, which also plans to produce vehicles in Nanjing, China.
About 550 jobs are expected to be created in Okalahoma.
Councillor Mike Whitby, leader of Birmingham City Council, said US involvement was an "exciting boost" for Nanjing's "plans to resume car production at Longbridge".
"Adding more partners to the project can only help to open up new markets for their products, which means more jobs in the long run for Birmingham people.
"We are hopeful that we will hear further details and information on Nanjing's long-term plans very soon."
Production at Longbridge stopped early in 2005, with Nanjing buying the company later in the year.
Nanjing's MG president and chief executive, Duke Hale, said: "We're positioning ourselves as a global car. Our position is to try to create a world-class car in a world-class company."