The 'Word of Warcraft' 8.3 update brings two new playable races.
Gamers will be able to play the Mechagnomes for the Alliance and the Vulpera for the Horde Allied races.
The races can be unlocked by finishing their storylines.
The update, which is titled, Visions of N'Zoth, also brings a new story involving both the Alliance and the Horde races.
Meanwhile, developers Blizzard recently revealed they cancelled 'World of Warcraft' follow-up 'Titan' because it was too "ambitious".
Founder Mike Morhaime - who has since left the company - said the project "struggled to come together" because the developers didn't "control scope".
He said: "We failed to control scope. It was very ambitious. It was a brand new universe, and it was going to be the next generation MMO that did all sorts of different things, it had different modes. We were sort of building two games in parallel, and it really struggled to come together."
Instead, Blizzard developed 'Overwatch' from the ashes of 'Titan', and Mike believes green lighting the multiplayer first-person shooter was "one of the best decisions [they] made".
He added: "We took something that wasn't going to ship for a very long time, might never have shipped, and turned it into an awesome game."
And 'Overwatch' director Jeff Kaplan, who worked on 'Titan', remarked: "We failed horrifically in every way ... In every way that a project can fail. It was devastating."
'Titan' was officially axed in 2014, and Mike said at the time the company just couldn't "find the passion" for the overly ambitious project.
He said: "We set out to make the most ambitious thing that you could possibly imagine. And it didn't come together.
"[Blizzard] didn't find the fun ... didn't find the passion."