"Do the opposite of what I did, and you'll be fine," she said in an interview with The New York Times Magazine.
When asked what went wrong when she and James Franco hosted the Academy Awards in 2011, she replied, "I think it's so obvious that it doesn't even need to be identified."
Hathaway added of Harris, "He'll be great. He's a natural host."
The actress has become a pretty good sport when it comes to talking about her experience hosting the Oscars. In November, she told "Tonight Show" host Jimmy Fallon, "The thing about me and embarrassment is you have to remember is that it all happens on a scale. If you think about embarrassment on scale of 1 to 10, 1 being a person walking down the street and 10 is, for me, co-hosting the Oscars with James Franco."
The Oscars will air live on ABC on Feb. 22, with Harris as host. Nominations will be announced Jan. 15.