"Hayden is totally pregnant!" the insider tells Us of the Nashville star, 24, who has been engaged to Klitschko, 38, for a year.
On and off since meeting at a book party in 2009, the Heroes alum and her 6-foot-6 boxer beau dated for two years before splitting in 2011. By the spring of 2013, however, they were back together and ready to spend the rest of their lives with each other.
Speaking about her future with Klitschko in an interview with the May 2013 issue of Glamour just a few weeks after Us broke the news of their engagement, the petite blonde actress expressed her desire to start a family.
"I've lived a very big life, and I don't feel my age, and I feel like I was born to be a mother," she said. "Sometimes people speak about [having kids] like, 'Your life ends—you're never going to be able to do anything again!' And I'm like, 'What are you talking about?' Motherhood is the most beautiful, exciting thing, and there's nothing that I feel like I can't accomplish while having children in my life."
She even joked about what her kids with Klitschko might look like. "He's got bowlegs and I've got knock-knees, so they're going to have straight legs," Panettiere quipped during an appearance on The Ellen DeGeneres Show in November 2013. "And they'll be normal height."