Hayden Panettiere is a lover, not a fighter. Wladimir Klitschko, however, happens to be both. The Ukrainian-born boxer defended his WBA, IBF and WBO heavyweight titles when he challenged Italian-born Francesco Pianeta in Mannheim, Germany, on May 4. The fight marked the 60th win and 52nd knockout for Wladimir, who began boxing in the early '90s.

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Panettiere cheered for her fiance with Natalia Klitschko, Wladimir's sister-in-law and wife of fellow boxer Vitali Klitschko. The 23-year-old Nashville actress looked like a knockout herself in a cleavage-baring dress.

In March, Us Weekly broke the news of Panettiere and Wladimir's engagement; neither has publicly commented on their impending nuptials. The couple reconnected in January after ending their two-year relationship ended in the spring of 2011. Panettiere spoke about their on-again romance in the May 2013 issue of Glamour. "It's like the 2.0 version," the Golden Globe nominee explained. "I've always had great relationships and stayed really good friends with the guys I've dated."

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When asked about getting married at a young age, Panettiere told the magazine she's always moved at a fast pace. "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. 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. I would sacrifice having more years of being wherever I want whenever I want for years with my kids."

This article originally appeared on Usmagazine.com: Hayden Panettiere Cheers on Fiance Wladimir Klitschko at Boxing Championship