Honda, Toyota and Nissan could all be represented in the DTM starting in 2014 following a deal between DTM organizer the ITR, and bosses of the Japan-based Super GT championship.
The ITR announced on Tuesday that an agreement has been reached with Super GT organizer GTA to allow that series to use the DTM's technical rules package as the basis for its cars from 2014-18.
ITR chairman Hans Werner Aufrecht said: "This is a very special day for all those involved but, in addition, it also has got outstanding significance for the entire motor racing world. This unique cooperation was made possible by the right parties getting involved at the perfect point in time.
"This cooperation of GTA and ITR based on the new technical regulations is a dream come true. We believe that this milestone in motor racing history will not only help to reduce the costs dramatically but, at the same time, it also should help improve safety and create spectacular racing with equal chances for the manufacturers and teams, thus entertaining the millions of fans all over the world."
The deal opens the door for the DTM's three manufacturers, Mercedes, Audi and BMW, to compete in Super GT with cars initially built specifically for the German-based series. The German manufacturers were represented in Japan for the signing of the deal by head of Audi Sport Wolfgang Ullrich, who said: "The GTA, ITR and the manufacturers involved are entering virgin soil.
"Super GT and DTM have got many common ideas. Now, these organizations are going to cooperate on the basis of shared technical regulations. A move that will guarantee spectacular sport, cost-efficient motor racing and maximum safety."
Until the cars in both championships are running to the same chassis and engine regulations, they will be equalized using a Balance of Performance system, for what was described as a transitional period. The DTM's current technical regulations came into force this year. Central to the ITR's plan to cut costs and increase the spectacle and safety elements of the sport are 57 spec parts, including the chassis, ECU and diffuser.
The DTM has been trying to arrange joint operations with organizations in the U.S. and Asia since 2010, although its association with Grand-Am was put on the back burner following the Grand-Am/American Le Mans Series merger agreement.