FOR four decades, he has been the nation's favourite uncle.

Now, as he prepares to celebrate his 70th birthday next Friday, Gay Byrne is about to be promoted. Uncle Gaybo is set to become a grandfather ? courtesy of his younger daughter Suzy and her husband, Ronan O'Byrne, who are expecting their first child next month.

For the Byrne family, Gay's 70th birthday is just the latest in a whole series of milestones. Four weeks ago, Gay and his wife Kathleen Watkins celebrated their 40th wedding anniversary. Their first grandchild is due on 26 September, and four days later their elder daughter, Crona, will get married in Spiddal, Co Galway. Then, before the best frocks are put back in their boxes, they'll receive another outing in October, when Kathleen joins her husband on Septuagenarian's Row.

Crona Byrne describes it as "four months of madness for the Byrne household" ? and given the scale of the celebrations to come, the family has decided to make Gay's birthday a low-key affair at their summer home in Dungloe, Co Donegal. "It'll just be a quiet celebration for family and a few friends, " says Crona.

"We've so much on this year, everyone agreed that we wouldn't make too much of a fuss over Dad's birthday." RTE will screen a special tribute show tomorrow night to mark this latest cause for cake in the Byrne household.

Michael Parkinson, Bob Geldof, Mike Murphy and Tommy Tiernan ? who wrote a whole show about being "crucified" on the Late Late Show and won the Perrier comedy award for it ? are among those paying tribute to the world's longest serving chat-show host.

Meanwhile, a whole new career looms for the broadcaster. The female members of the Byrne household have already decided that Gay will be a hands-on grandad. "We'd hate to think he'd get to retire in his retirement, " says Crona, who worked as a nanny for nine years. "He's being trained in at the moment." In fact, the entire Byrne household seems focused on pitter-patters of a sort at the moment. Crona, who moved from Dublin to Ballina 18 months ago, has just opened a toy and gift shop, Happy Days, in Nenagh with her fiancé, Phil Carney. Crona ? who has "done everything" ? used to work as a coordinator on the Late Late Toy Show so she's familiar with the market.

"After so many years on the Toy Show, suddenly opening boxes of toys again I thought, 'Oh, God, do I really want to do this again?'? God, I sound like Dad now!"