The footballer turned businessman will wed girlfriend Fiona Creely tomorrow and then host a luxury bash at the K Club in Kildare.
He will be joined by a host of his Dublin GAA pals for a lavish party at the five-star resort, which famously hosted the Ryder Cup in 2006.
The football heroes had plenty to celebrate this year after winning the All-Ireland title – their third in five years – with victory over Kerry in September.
Fennell, who owns shoe company Sole Sister Flats, has been building his media profile in recent years with a variety of radio roles.
However, he told the Herald that the wedding has been taking up all of his time in the weeks running up to the big day.
“It’s certainly been all go and there has been plenty to do so that has been my priority lately,” he said.
“A good few of the Dublin lads will be there, and we’re really looking forward to it now. It’s going to be a really great day.”
Fennell, who bought his wedding suit from tailor to the stars Louis Copeland, went down on bended knee while on a trip to New York with Fiona last New Year’s Eve.
And he was not letting nerves overcome his excitement in the lead-up to the big day.
“We’ve been together for over four years now so it’s about time,” he joked.
Fennell was a member of the team that beat Kerry to the All-Ireland title in 2011 and has dabbled with TV and radio appearances since.
Before meeting Fiona, he appeared on TV3 dating show Take Me Out.