The proud mum, who also has 3-year-daughter Belle with rugby husband Ben, uploaded the video to Instagram, with the caption, "He said Hello!! 12 weeks old (well I'll believe he did anyway lol) #Tadhg".

Una, 33, can be heard encouraging the tot to say hello, before he responds with what sounds like a warbled- but adorable- 'hello'!

So cute!

The Voice of Ireland coach recently revealed she would love to duet with her winning contestant Patrick Donoghue.

Speaking about his career, she told the Herald:

"I'm going to be there behind him all the way as well. I'll be giving him all the advice that he needs and I would love to sing with him sometime, I would absolutely love to.

"I believe he will [be famous]; the world needs to hear his voice. When you've got talent like that, I just can't see it fail," she said.