The BAFTA and Golden Globe winner - known for her roles as Molly Weasley in the Harry Potter movies and Susan 'Rita' White in Educating Rita - told The Guardian that a parrot caused havoc during a 1991 stage production of Tennessee Williams's The Rose Tattoo.
Walters said: "We had this urn where my husband's ashes were meant to be, and it kept spontaneously breaking on stage. We also had a live parrot in a cage, which had learned half my lines. It kept shrieking, 'Give me a sign!'
"One night, I saw that it had opened its cage and was creeping out. I thought, 'God's sake, he's going to fly out and crap all over everybody'. After that, we got a stuffed one."
Walters also revealed that she only realised the impact that acting has on her health when she filmed BBC One drama A Short Stay in Switzerland.
Earlier this year, she was named by Coronation Street producer Phil Collinson as the actor that he would most like to cast in the ITV1 serial.
Collinson said that he believes Walters would make "a great double act" with Audrey Roberts (Sue Nicholls).