Spanish actress Elsa Pataky has been cast as the superhero's girlfriend in Maltes Producciones' $30 million Captain Thunder. She will play Sigrid of Thule, a Viking princess, according to The Hollywood Reporter.

"It would be difficult to find a more perfect actress for the part of Sigrid," producer-director Pau Vergara said. "Elsa is bilingual, she even physically resembles Captain Thunder's girlfriend and she's a tremendously popular actress in Spain and known in Europe."

Walt Disney Motion Pictures Iberia holds Spanish rights and first option on U.S. distribution for the adventure movie based on Spain's most popular comic book hero, known as "Captian Trueno" in Spanish.

Captain Thunder is a 12th-century knight-errant who wanders the world fighting injustice and is accompanied by his faithful friends Crispin and Goliath.

The movie, which already has sold to more than 53 countries, is set to begin shooting in July 2009 at Spain's new studio facilities Ciudad de Luz in Alicante.