Oisín is the second child for Tahyna and her Dancing With The Stars husband Tristan. The couple are also parents to daughter Echo, 2.
Last year, Tahyna revealed that she had previously suffered three miscarriages.
"I had gone through three miscarriages before finally founding out that I was pregnant and I think for the most part that I really realised that there was need for a conversation and a dialogue," she previously told The Morning Show on why she opened up about her loss.
"I decided to share it because I remember when I was going through mine I was feeling really alone."
Watch the interview below:
This article originally appeared on WHO