Heigl took to Instagram to give us a peek at their growing bundle of joy via a sonogram, writing: "@joshbkelley and I have some news...go to thoseheavenlydays.com and I'll tell you alllllll about it!"
The expectant star also shared the image on her blog, where she penned a lengthy post about the family of four's coming addition. The duo is already parents to two daughters, Adelaide, 4, and Naleigh, 7, who joined the family in 2009 and 2012 through adoption. "Sooooo….the Kelley family received some very exciting news recently and I’ve been dying to share it with you all. We are expecting a third addition to our tribe! It was totally unexpected but thrilling nonetheless," she wrote. "Naleigh and Adalaide are over the moon and can not wait to spoil their new sibling rotten and of course Josh and I are full of high hopes and bubbling anticipation. The whole pregnancy thing is new to me but the thrill of having a baby is not....I wasn’t sure pregnancy was even in the cards for us. Turns out it was very much in the cards!"
Go to Heigl's blog for more photos and to read the full post.