Michael Bublé feels like his son's a "genius" when he poops.

Michael Bublé and Luisana Lopilato

Michael Bublé and Luisana Lopilato

The 'Haven't Met You Yet' hitmaker is thrilled that 20-month-old Noah's toilet training has gone so well, admitting everything the little boy does is "cute".

He gushed: "He's 1 year and 8 months, and when he poops, I feel like he's a genius - no other kid can poop the way that he does.

"Everything is cute. He's the best. What I like is, I ask him to do this face. I say, 'Cara dulce,' which means, 'Do your sweet face.' And he does this cute little face. The kid kills me."

And the 39-year-old crooner and his wife Luisana Lopilato are desperate for their family to grow.

He shared to PEOPLE magazine: "Me and my wife would really love to have three or four, five [kids], if we're blessed to do that. And if we can't do it naturally, then we'll do it another way - we'll adopt."

Meanwhile, Michael previously admitted he is finding fatherhood "surreal".

He shared: "It really wasn't what I thought it would be. Everyone told me it would be this life-changing, massive, you know... but it was very surreal.

"Until you do it, you don't know and now I know that we'd love to have three or four more... a litter, exactly."