When The Stranger and The Dark Wizard’s paths finally cross, it's confirmed that they know each other from before all of this. It’s well known that Saruman was the first wizard to arrive in Middle-earth. Then this line seemingly alluded to the fact that in Rings of Power, this magical being was also the first of the five wizards to land there:

So, if the Stranger is Gandalf, then that means the Dark Wizard is either Saruman, Radagast, or one of the two Blue Wizards. Considering the Dark Wizard certainly looks a lot like Saruman, and refers to Gandalf as "old friend," it seems pretty safe to conclude that he is indeed Saruman the White.

The first season of The Lord of the Rings: The Rings of Power loved its mysteries — a secret Sauron, a spooky sword, and an amnesiac meteor man. And while we had a pretty good idea of who that meteor man was at the end of season 1, the finale of season 2 finally gives him a name.