This "to be or not to be story" starts to look exactly like the one with Ferrari Dino. Last week we reported that Cadiilac is working at a V12-engined supersedan that will compete with the Mercedes-Benz S-Class and the Lexus LS 460. But Holden's engineering chief has denied this rumors: "It’s definitely not happening."

Mr Lutz, GM’s global product development chief, is reported to have said at a Hummer dealership opening in Britain that Australian engineers were already working on the new V12 engine.

There were also rumors that the V12 is already being tested at Holden’s Lang Lang test track in Victoria. However, Mr Hyde said that Holden was not working on anything remotely like a V12 Cadillac. “We are definitely not doing it,” he said. “It might be possible to join two V6s, but we are not doing it.

"We are not working on any Cadillacs," said Mr Hyde. "Nothing. We’re full-up in terms of resources with Camaro and our own cars. (And) the G8 is a challenge from a timing point of view."