Both Garbo and Dead were reclusive and esoteric, and both seemed entirely absorbed in their respective arts and in their own cultivated personae, and certainly both were known for their, shall we say, distinctive voices. Both were dour and brooding, and were rarely caught smiling; neither of them were known for their humor. Finally, both are remembered by posterity for being titans in their respective crafts.
Of course, I'll be the first to admit that they have their differences--Dead didn't wear gowns by Adrian, was never nominated for an academy award and could never conceivably be linked romantically to John Gilbert. Likewise, Garbo never buried her clothes for days before wearing them on camera, didn't keep a dead bird in a bag for the purpose of "inhaling the smell of death" and most likely wasn't fond of self-mutilation (at least not to the point that she had to be taken to the hospital for blood loss). Finally, the two died under vastly different circumstances--Garbo lived to the ripe old age of 84, whereas Dead committed suicide at age 22 (and in quite a grisly fashion, I might add).
I can only imagine the chaos that would have ensued had Garbo killed herself at the height of her fame (although I can imagine that Joan Crawford would have taken pictures of the gruesome scene before reporting it to anyone, much like Euronymous did. She just seems like that sort of gal).
Regardless of their fellow actresses or bandmates, however, these two secretive and unusual personalities will always bear an eerie similarity in my mind. And you should count yourself lucky that I didn't decide to throw ABBA into the equation!
Addendum: As it turns out, Greta and Dead are buried in the same cemetery: Skogskyrkogården, in Stockholm.