Carrie Underwood's son talks to his unborn sibling.

The 35-year-old country singer is expecting her second child with her husband Mike Fisher, and has admitted their three-year-old son Isaiah has started to ''talk to'' Carrie's burgeoning baby bump as he tries to converse with his unborn younger sibling.

When asked if Isaiah is aware he's about to become a big brother, Carrie said: ''I don't think for real he does. He'll be really sweet and talk to my belly and kiss my belly. He's the sweetest little boy. I mean, no kid can really know that their life is going to change. He'll just have to share mommy.''

The 'Cry Pretty' hitmaker and her spouse have even tried to incorporate their son into the planning for their new arrival, but Carrie admits it hasn't quite gone to plan.

She added: ''We did ask him [if he had a name suggestion], and he did say, 'Isaiah Michael Fisher,' which is, of course, his name and would be confusing. He wants to name everything his name because he thinks that's special.''

And when the family aren't busy planning for baby number two, Carrie says she's focused on her son's talents, as she ''really wants him to sing.''

When asked during an appearance on 'The Tonight Show starring Jimmy Fallon' on Thursday (13.09.18) if she listens to Isaiah singing, Carrie said: ''I try, is that wrong? I'm like judging my three-and-a-half-year-old child to see if he can sing.

''If he is not musically inclined that is fine. I'm excited to find out what he loves and is passionate about and is good at, and I will support that. But I really want him to sing.''

Meanwhile, a source recently claimed the 'Before He Cheats' singer is being ''doted'' on by her 38-year-old former NHL star husband during her pregnancy.

An insider said: ''Mike is being the most doting, amazing husband while Carrie pregnant. Mike tries to take Carrie out once or twice a week for date night in Nashville.

''[He is] reading a bunch of parenting books, rubbing Carrie's feet and is making sure she is happy and comfortable at all times.''