"In honor of 'Labor' Day ... Ace & Penny would like to make an announcement. Their parents couldn't be happier!" the 31-year-old posted Monday afternoon on Twitter and Instagram, along with a photo of her cuddling up with the couple's two T-shirt-wearing dogs. One dog's outfit reads, "I'm going to be a big brother"; the other's says, "I'm going to be a big sister."
Fisher, 34, a center for the
The announcement led to a bit of confusion, with some people wondering whether the new arrival would be a human or a puppy.
It's the first child for Underwood and Fisher, who tied the knot in 2010 and have long been beset by pregnancy rumors. The six-time Grammy winner played a little coy in the wording of her pregnancy announcement, but she has been more direct on social media on other occasions.
A year ago, she took a tumble onstage, then joked about it and engaged in some mutual teasing with fellow country crooner Brad Paisley.
And last December, Underwood exulted online after her widely watched turn as Maria in "The Sound of Music Live!" on NBC. When the haters emerged, she fired off another tweet to tell them she wasn't taking their gibes to heart.