"This is the actual pic I sent my husband this past Mother's Day while lying on the bathroom floor," the 36-year-old actress wrote. "I had just returned from Israel, was jet lagged, and didn't believe my eyes. So had to obviously be @Clearblue 5x over sure. We are SO excited to announce the #ClearblueConfirmed arrival of another little one in just a few short months ???❤ #clearbluepartner."
Sigler and Dykstra had their first child, son Beau, in September 2013, and married in January 2016.
"My favorite thing about being a mom [is how] he just says how he feels," Sigler told ET in April. "We love being parents, so we're definitely talking about and hoping to expand our family eventually."
Looks like eventually is here! Congrats, Jamie-Lynn!
Watch the video below for more of what Sigler has said to ET about her family.