That was until she handed him a fishing rod and he "looked at me and said: `And one for Ladybug'."
Leo Broderick was 2 at the time and it was the first his mother had heard of his imaginary friend.
"She used to come everywhere with me, everywhere I went," Leo said.
He remembers writing stories about her and being afraid of her flying away out of open car windows.
Miss Couch said Ladybug "seemed to drop off" when Leo started school, but she agreed with new University of Otago research which shows imaginary friends having a positive impact on children's language development.
"Leo has quite good academic achievements [and] his language skills were strong from a really early age, and it seems to tie in with what they [researchers] say," Miss Couch said.
In the study, which appeared in the latest issue of the journal Child Development, Assoc Prof Elaine Reese and co-researcher Dr Gabriel Trionfi investigated the language skills of 48 children aged 5, 23 of whom had imaginary friends.
They found those with imaginary friends had more advanced narrative skills than those who did not.
"We believe that the children in our study with imaginary companions got extra practice at telling stories when they told others about their imaginary friends or when they had conversations with their friends," Prof Reese said.
The research suggested parents and teachers should not be concerned about young ones having imaginary friends, and it further dispelled the belief they were bad for children, she said.
