Borderlands 2 remains on course to become 2K's biggest-selling game in its history, with worldwide shipments now standing at approximately 6 million, Take-Two has announced.

Take-Two's chairman and chief executive officer Strauss Zelnick told investors that the game has also been a big contributor to the publisher's digital revenue.

"Borderlands 2 was the largest contributor to our digitally delivered revenue last year based on high demand for the game's innovative downloadable add-on content, as well as full game downloads," Zelnick told investors during last night's Q4 earnings call.

Back in February, Zelnick said Borderlands 2 was approaching 6 million units shipped.

The game's latest DLC, Krieg The Psycho, is set to release later today, followed by Tiny Tina's Assault on Dragon Keep on June 25.

Source: Seeking Alpha