Yep, this is real:
Rosario Dawson has joined season 2 of “The Mandalorian” in a role which will have “Clone Wars” fans brimming with excitement.

The “Briarpatch” star has been cast in the guest starring role of Ahsoka Tano, Variety has confirmed. Tano is Anakin Skywalker’s apprentice and one of the central characters in the popular animated “Star Wars” series. This will mark the character’s first live-action appearance, after being voiced by Ashley Eckstein on all seven seasons of “Clone Wars,” the final season of which is currently airing on Disney Plus.
This may not seem like a big deal, but many Star Wars fans were pushing for a live action version of Ahsoka, with Rosario Dawson as the dream candidate. Dawson herself, had express interest in portraying Ahsoka.

The Mandalorian Season 2 is scheduled for this Fall.