Underwood is due in January next year.
And her journey to this pregnancy has been bittersweet.
The mum to three-year-old Isaiah, who she shares with husband Mike Fisher, admitted that, “It took us a while to get here … I’m gonna cry again.”
Underwood suffered three miscarriages prior to her most recent pregnancy.
“[I’m] just so thankful … to find out Isaiah’s gonna have a baby brother. It was just great news. We’re excited.”
Things are a little different this time round.
"When they say every pregnancy is different, it really is. Just different symptoms."
"I feel like this one is just a little harder on my body for some reason. But it's been really good."