BFR has been renamed to Starship. Musk elaborates that Starship technically consists of two parts. You have the Starship spaceship/upper stage and Super Heavy as a rocket booster. The Super Heavy booster is only required to escape Earth's deep gravity well, it's not needed for other planets or moons.
Technically, two parts: Starship is the spaceship/upper stage & Super Heavy is the rocket booster needed to escape Earth’s deep gravity well (not needed for other planets or moons)— Elon Musk (@elonmusk) 20 november 2018
The first test flight of Starship is expected in 2020 at the earliest.
On a related note, Musk also mentioned that SpaceX is no longer planning to upgrade the second-stage of the Falcon 9 for reuseability. Instead, the space launch firm is accelerating the Starship. These two rockets will be the workhorses of SpaceX. Falcon Heavy is expected to see limited use, as most of the launch volume that was originally intended for that rocket can be handled by the cheaper Falcon 9 Block 5 booster.