An adopted girl used a school bus for seven years without realising the conductor was her natural mum.
Carole Davies, 64, was born to mum Freda Pickering, 83, in 1948 following a wartime romance, and was almost immediately taken into care.
But after tracking down her natural mother, Carole discovered her mum had issued her a ticket every day on the school bus to Tadcaster Grammar, West Yorkshire.
Carole, 64, of Dudley, West Midlands, told her local paper: "It's amazing - she checked my ticket daily."
Freda said: "I never dreamt this would happen." Carole was born following a wartime romance between Freda and a Croatian youth who worked at a camp near her home in Wetherby, West Yorkshire.
But with no prospect of marriage Freda, 19, was persuaded to have her newborn taken into care. She thought she would never see her daughter again.
Almost 60 years passed before Carole, a teacher from Dudley, West Midlands, unearthed their story as she attempted to trace her birth mother.
"It's unbelievable to think we were so close to each other for all the years Carole was at school," said Freda, 83.
"I don't think I would have said anything even if I had known because I had to wait for Carole to make the first move. It's nice to think I was a part of her life when she was younger."
Carole said Freda had asked her whether she went to Tadcaster Grammar School, and if she travelled by bus.
"I replied, 'Yes, twice a day' to which mum said, 'I was the bus conductor.'
"I had no idea that the lady who checked my bus pass twice a day was my mum. It was a complete shock. I don't really remember anything about the bus conductor, and all along it was my mum. It's incredible how we've been able to find each other."
Carole, 64, had been brought up by Tom and Dorothy Freeman, who made no secret of her adoption. She has two children of her own, and it was daughter Michelle who found Freda through an internet ancestry search.
Armed with her birth mother's name and address, Carole plucked up the courage to write a letter which began: "Before you start to read this letter, I suggest that you make yourself a cup of tea."
The letter added: "I don't really know why you were unable to look after me, but whatever the reason, I believe you did what you thought was best, or had to do, at that time."
Freda phoned Carole as soon as she finished reading the letter. "It was so strange hearing my daughter's voice," she said.
Freda started work as a conductor for the West Yorkshire Road Car Company in 1954, where she met bus driver Ron Pickering.
They married the following year, but had no children despite both being desperate for a family.
When Ron died in 2004 Freda thought she was all alone. But a year later the unexpected letter from her daughter arrived.
It revealed Freda was not only a mother, but also a grandmother and great-grandmother.
Freda added: "It is lovely to get to know them all and we do have a proper mother-daughter relationship, though I do find Carole a little bossy." Carole said: "We keep in contact as much as possible."