The new compact editions of flagship Fairfax mastheads The Sydney Morning Herald and The Age will be printed for the first time on Monday, March 4, it has been confirmed.

Commercial director Ed Harrison has hailed the news as "a historic event for Fairfax", with the new editions to be sponsored by BMW.

Plans for the downsizing from broadsheet size were announced last year under the Fairfax of the Future strategy, which also saw huge structural shifts and job losses at the publisher.

Harrison added: "The size of our papers is changing, but the quality certainly isn't."

Under the ad agreement BMW, itself currently in the middle of a drawn-out media pitch, will "Metroblock" both titles for the day, "effectively owning" them in print and the digital editions.

More details of the new editions and mock ups of how they will look are being revealed to media at a briefing in Sydney this morning.