Karina Smirnoff and fiance Brad Penny have reportedly split.

"They are just two different people," a source told E! News.

Smirnoff -- who won her first Dancing with the Stars title and mirrorball trophy when she and celebrity partner J.R. Martinez were crowned thirteenth-season champions last month -- and the Detroit Tigers pitcher's representatives have reportedly declined to comment.

Smirnoff began dating Penny in October 2009, shortly after she and fellow Dancing with the Stars professional dancer Maksim Chmerkovskiy called off their engagement and ended their relationship. Penny then proposed a year later in October 2010.

Smirnoff and Penny had set January 21, 2012 as their wedding date, but the 33-year-old dancer postponed the ceremony in October claiming her relationship was fine but the couple's careers were causing time constraints. While Penny was in the playoffs, Smirnoff said she owed Martinez her full attention in the Dancing with the Stars competition.