Like its German compatriots - and its hatch sibling - the new four-door 1 Series will ride on a front-wheel-drive platform, likely sharing its engines with the new Cooper.
For now, the new model is believed to be known as the New Entry Sedan (NES), and its development has been spurred by the growing demand for small prestige models.
“The NES is integral to our growth plans,” an unnamed BMW insider told website AutoWeek.
“It will be an important pillar in the future 1-series lineup, particularly in the U.S. and China, where sales of small premium-brand four-door sedans are on the rise."
Models in the new 1 Series range are expected to be offered with small three- and four-cylinder turbocharged petrol and diesel engines, and a plug-in petrol-electric hybrid model is also rumoured.
And, again like its Audi and Mercedes rivals, the new front-wheel-drive 1 Series will also come with the option of an all-wheel-drive system.
For its part, BMW has yet to confirm the coming of a new small sedan, but reports suggest a 2017 debut may be on the cards.
Watch for the taller 1 Series GT hatch to debut first - likely while the current 1 Series range is still in showrooms - and new sedan and hatch models to follow.