Previn won four Oscars for his orchestrations of such stylish musicals as 1964's My Fair Lady.
Slatkin posted a picture on Twitter of Previn saying he "deserved better".
The academy says all mentions on its website will feature accurate imagery of Previn.
Slatkin has been having a good-natured laugh about the whole thing though, even appearing on Jimmy Kimmel to "prove" he is very much alive.
"Some people might wish [I was dead] but no. I was really shocked. Instead of giving their best to Andre Previn, they wound up giving their worst to me," he said.
Slatkin said of Previn: "I knew him very well... he did it all, he was a great gentleman. I was just so sad that he couldn't be remembered the way he should be."
However, he added: "They talk about people spinning in their graves - Andre's not spinning, he's laughing."
-with AP