Carrie Underwood says being a mother of two will be ''a different ball game''.

The 'Before he Cheats' hitmaker and her 38-year-old husband Mike Fisher - who already have three-year-old son Isaiah together - announced earlier this month they are set to expand their brood as Carrie is pregnant with their second child, and the star now says she's doing her best to plan ahead before the new arrival comes.

She said: ''It's going to be a different ball game, for sure. My brain, I'm such a planner. I want to know how it's all going to go. But no matter who you are, you make it happen, you make it work, you get your team behind you.''

The 35-year-old singer is hoping that all hands will be on deck to help around the house once the tot is born, and she's confident Isaiah will be a ''really good big brother'' to his new sibling.

Carrie added: ''I think he'll be a really good big brother. I think he'll be helpful.''

The 'Cry Pretty' singer also addressed speculation about the sex of her baby, after it was rumoured she would be having a little girl.

She told The Tennessean: ''I don't know what it is. You've got a 50 percent chance you're correct. I have no idea.''

Meanwhile, a source previously said Carrie couldn't be happier to be pregnant again, as it comes after a tough year which saw her suffer a serious accident for which she had to undergo surgery for a broken wrist and receive more then 40 stitches on her face.

The insider said: ''This baby is incredibly exciting because it represents new beginnings after a very challenging year. She is ready to put her accident behind her and focus on her family and her new album release.

''Mike is thrilled because he desperately wanted another baby, and their son Isaiah even talks about a baby brother or sister, so the whole family is in celebration mode. When Mike and Carrie married he told her he wanted a large family, so this is a dream come true for him.''