The 85 year old has made history as the eldest nominee to ever compete for the Best Actress title at the Oscars, and she shares the category with the youngest ever nominee - Beasts of the Southern Wild's Quvenzhane Wallis, aged nine.
But Riva insists she never expected to be recognised, and was overwhelmed by the phone calls she received after waking up in New York when the nominations were announced on Thursday (10Jan13) morning.
She tells USA Today, ""I feel like I'm in sort of a fairy tale. I did not expect such a success. I was living my life by the moment.
""I like it. I like the situation of being the oldest nominee and sharing it with someone who is extremely young.""
The actress admits she knew immediately she was the right woman to play ageing pianist Anne in the drama, adding, ""When I read the screenplay, I had the very intimate feeling that I was going to be able to do it, and I say that without any kind of vanity. The timing was perfect.""
The upcoming Academy Awards in Hollywood will be extra special for Riva - the ceremony falls on her 86th birthday (24Feb13).