The actor is dating Modern Family star Sarah Hyland and will now play a love interest for her character Haley, Zap2It reports.
His character Ethan is a good guy who moves to town to go to college, according to TV Guide.
Ethan is the nephew of one of Claire's friends, so she decides to introduce him to her daughter.
Prokop has previously appeared in movies like High School Musical 3 and Furry Vengeance and will also appear alongside Hyland in Glee star Chris Colfer's upcoming film Struck By Lightning.
Barry Corbin recently signed up for a guest role in Modern Family, while Britney Spears has said she would like to appear on the comedy.
Modern Family airs on Wednesdays on ABC in the US and on Fridays on Sky1 in the UK.