Danny DeVito Planning New Original Movie With Arnold Schwarzenegger

Danny DeVito's getting back together with his onscreen twin -- saying he and Arnold Schwarzenegger are set to team up once again ... in a totally new project.

The actor spoke with Fox News Digital Wednesday -- days after his surprise appearance alongside The Governator at Sunday's Oscars ceremony -- and said he and AS have plans for a silver screen reunion.

In fact, Danny says this isn't just some hopeful whim -- he says a script is actually in the works, and Warner Bros. is involved ... so, it seems like this thing is really happening!

"Twins" fans shouldn't get too excited though ... 'cause DD says this is an all-new flick, not a sequel to the hit 1988 film starring Danny and Arnold as fraternal twins.

Danny said that his and Arnold's friendship stretches even further back than "Twins" saying they'd see each other every so often ... but -- as Danny joked -- they weren't pumping iron at the gym together!

Ultimately, Danny says they're hoping to start production next year ... and, he's keeping his fingers crossed the project won't be delayed.

Arnold's got a whole bunch of projects on the way according to IMDb FWIW ... and Danny's gonna be featured heavily in the 17th season of his hit show "It's Always Sunny in Philadelphia," so the two guys are gonna have to work around busy schedules.