For years, they passed each other in the street - without so much as a flicker of recognition.
But to the amazement of Ken Whitty, the woman was not a stranger, but his long-lost younger sister Yvonne.
The discovery came four decades after they had lost touch, when the 64-year-old appealed for help in tracking her down - oblivious to the fact that they lived only 300 yards apart.
Yesterday Mr Whitty told of his amazement that the woman he sometimes saw pottering in her front garden was actually his little sister, who is now 62.
After being reunited this Christmas, they are now beginning to catch up on all that lost time.
'I've walked past her house lots of times and I've even seen her in the garden,' he said. 'I am in my 60s now and so is Yvonne, and the last time we saw each other was 40 years ago.
'We have changed so much that we just wouldn't have recognised one another.'
The pair were brought up together in Salford but their parents both died when Mr Whitty was barely into his teens.
They were raised by a family friend but drifted apart after they both left home.
They finally lost contact in 1970 when Mr Whitty went round to the house where his sister had been living - only to find it had been demolished. Since then, he has found work as a joiner, moved to Reddish, Greater Manchester, married his wife Carolyn, and had four children and six grandchildren.
His sister also married and had four children and ten grandchildren.
Over the years, Mr Whitty tried to find out what had happened to the woman he still calls 'our kid' but he was unable to discover if she was even still alive.
'I thought we would eventually get back in touch but time went by and it never happened,' he said.
'I thought, it's Christmas, I'm 65 next year and I've got to do something. I just had to do it this year.'
So he posted a message in the local paper asking for help getting in touch with her and almost immediately received a phone call from an old school friend.
Within minutes the phone rang again, and he heard the words: 'Hello, this is Yvonne.'
'It happened just like that,' he recalled. 'I couldn't believe it. I asked her where she was living and she said "Reddish",' he said. 'I asked whereabouts, and when she said "North Reddish". I said, "So do I".
'It turned out we'd been living just 300 yards away. I shot round to see her and it was great.'
His sister, who has reverted to her maiden name, added: 'It's so nice to see Ken again. It's just so overwhelming.'