Panettiere had been seen earlier this summer sporting a ring on her engagement finger, but no announcements of an engagement were made.
Panettiere, 24, is currently staring in the drama series Nashville that airs on ABC on Wednesday nights at 9:00 CST. The actress portrays a country music singer, Juliette Barnes, and does a fantastic job with vocals.
The couple first met back in 2009 at a block party. Panettiere dated Klitschko for several years before breaking up in 2011. The couple got back together earlier this year and it seems like this time may even make it down the aisle.
Klitschko is 37 and lives in Kiev. He has earned the nickname "Dr. Steelhammer" after 52 KO's during his professional career. Klitschko is currently the WBA/IBF/WBO and IBO world heavyweight champion.
Click here to see Hayden Panettiere's huge engagement ring!