In her video, posted on Derek Hough's Instagram page, Panettiere is seen calling on both baby daddy Wladimir Klitschko and their "unborn child" to follow suit. Hough then pours a bucket on her head and we get a good look at her growing belly through her wet shirt.
It was just confirmed this week that Derek will appear on the ABC country music series this fall, so that explains why they're spending so much time together.
"Hayden shortly went into labor after this," Hough captioned the video.
Hayden isn't the only one who confirmed their pregnancy via her challenge video. Zoe Saldana did the same on Tuesday, though she had her husband Marco Perego take the ice bath instead.