Rugby legend Donncha O’Callaghan may be hanging up his boots in May, but he's hitting our TV screens this Sunday as a first-time coach on Ireland's Fittest Family.

And just as he sets out to encourage families across Ireland to prioritise fitness, he told us that his decision to call time on his 20-year rugby career was very much tied to his own family priorities. 

"What I have mistaken for sacrifices is really me being selfish," O'Callaghan said. "So I have to prioritise my wife and my four lovely kids and make sure that I’m there for them and we have an enjoyable time and that I take my bit of the loads."

But sport will still be central to his life – and he wants it to be important for his kids, too. "I 100% want my kids to be involved in sport, because I think it instills great values and you make great friends," O'Callaghan pointed out.

"But the big area for me is that you want them to be healthy, well, fit, happy and I think everyone looks for excuses."

Ireland's obesity crisis is a motivating factor for his involvement in the TV show.

"Sadly, at the moment, there is one in four of our kids are obese and everyone’s looking to blame different sectors.

"But I just look under my roof and realise that I’m a dad of these four beautiful kids and I’ve to ensure we get fit, healthy and well and they’ve a knowledge of nutrition."

"That’s what drove me to Ireland’s Fittest Family this year. My kids love watching it."

And one of the most important parts for O'Callaghan is how accessible getting fit is.

"You don’t need gym membership, you don’t need any equipment, you don’t need to be a part of a team. You have it there under your own roof."

The first episode of the fifth series of Ireland's Fittest Family is on RTÉ One on Sunday October 29 at 6:30pm.