Bethesda plans to offer an early access period for The Elder Scrolls Online's upcoming Morrowind expansion, but only for those who play on PC and Mac. Existing players on either of those platforms who purchase the digital upgrade of the expansion or the collector's edition can access Morrowind starting on May 22. That's a full two weeks ahead of the expansion's official release on June 6.
This access isn't limited to a portion of the expansion, nor is it only a preview where progress will be wiped afterward. Players will be on live servers and will not lose any of their progress once Morrowind launches in June.
Purchasing the digital upgrade or digital collector's edition before launch will get you into early access. Those who buy the physical version of the collector's edition will need to contact the game's support team in order to receive access.
While this isn't labeled as a beta, Bethesda did note that this early access period will "allow for final gameplay tuning and polishing before the game launches."
ESO: Morrowind adds to the MMO a new class (the Warden), storyline, and PvP mode, as well as the island of Vvardenfell from The Elder Scrolls III: Morrowind to explore. You can check out the system requirements here.