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".
I saw that @theemmys posted a photo of me "In Memoriam" rather than the intended Andre Previn. Andre deserved better. I had the opportunity to introduce him when he received the @KCHonors. Perhaps he was paying me back for a couple stories I told about him. Andre, R.I.P. pic.twitter.com/MDVX6H0igb
"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."