A remarkable coincidence will see little Ciara Coleman turning one on the same day that her great-grandfather, Michael Dowling, reaches the remarkable age of 100.

Although separated by 99 years they're united by blood and by the fact that the happy pair share the same birthday 99 years apart. That fact has made them the toast of their family with a joint celebration planned in Killarney, County Kerry today.

Dowling, whose wife Annie passed away in 2009, is a former civil servant and has five children, ten grandchildren and nineteen great-grandchildren.

His Dublin based granddaughter Mairead Dowling, the mother of little Ciara, said the pair are firm friends.

'When we go down to Killarney to meet her great-grandfather, she loves him. He's very good with all the great-grandchildren.'

She added that Dowling attributes his longevity to three elements.

'He would say it's down to three things – a good woman, God and uisce beatha (the Irish name for whiskey). He enjoys a glass of whiskey. There might be something in it,' she laughed.

According to the Irish Independent, extended family, friends and neighbors are traveling from as far afield as Canada, Italy, England and Wales to attend the big event in Killarney.

Dowling has already received a letter of congratulations from President Michael D Higgins marking his 100th birthday and will today be presented with a cheque for the Centenarian Bounty of $3,473.00.