The singer-turned-TV presenter and his former Hollyoaks star wife Jodi Albert became parents to son Koa in December 2011, and he is already showing he has inherited his dad's musical talent.
Kian revealed: "He's super interested in music. I sit him on my knee when I play the piano and I play the guitar to him, but he's definitely interested in music and he's definitely got an ear for it.
"He's already sitting there with one finger on the key on the piano rather than just slapping all the keys with his hand. And he's plucking the string, rather than just slapping the guitar. So he certainly has a little thing for it."
Kian is happy for Koa to follow in his footsteps and become a musician. "If it happens for him naturally that he wants to play piano and guitar then he will," he added.
Since Westlife split, Kian has become a TV presenter on This Morning and The Xtra Factor and a coach on The Voice of Ireland. And he revealed now he thinks of music as more of a hobby.
He said: "I write songs, but I kind of just do them for myself, just for the fun of it. Sitting jamming with my guitar and mucking around.
"I might play it to a few people and go, what do you think of this, but I'm not that kind of person that needs to get out there and push my songs in people's faces. It's not really me."