The on-again, off-again story of the super-sexy Cadillac Converj is on again.

So says John Voelcker of Green Car Reports, who cites an “inside source, a person close to the project” saying the plug-in hybrid — essentially a tarted-up Chevrolet Volt — is a go.

We’ve heard this a couple of times since General Motors unveiled the Cadillac Converj at the Detroit auto show two years ago. No less than an authority than then-GM vice chairman and vociferous Volt proponent Bob Lutz said early last year that the brass had approved it. Three months later, however, came word that GM had shelved the project.

It appears to be back. Voelcker’s source says management has approved production for 2013 as a 2014 model. It will feature “a Generation 1.5 Voltec drivetrain” with a little more oomph than the drivetrain underpinning the Chevrolet Volt.

We asked Cadillac spokesman Dave Caldwell about this. As usual, he essentially said, “Maybe.”