Casting Net: Colin Firth and Michael Fassbender to explore 'Genius.' Plus: Amanda Seyfried, Patrick Dempsey, Stellan Skarsgard

• Colin Firth and Michael Fassbender are set to star in the biopic Genius, about the relationship between literary editor Max Perkins (Firth) and celebrated author Thomas Wolfe (Fassbender), film sales company FilmNation Entertainment announced today. Screenwriter John Logan (Skyfall, Hugo) is adapting A. Scott Berg’s biography Max Perkins: Editor of Genius, and London theater fixture Michael Grandage will make his feature film directing debut.

• Amanda Seyfried and Patrick Dempsey will star in the romantic comedy Wonderful Tonight, about a one night stand that results in pregnancy. Christine Jeffs (Sunshine Cleaning) will direct from a script by J. Mills Goodloe (Pride). [Deadline]

• Stellan Skarsgård (The Girl with the Dragon Tattoo, The Avengers) has signed onto the dramedy Hector and the Search for Happiness, the film’s producers announced today. Based on the novel by François Lelord, the film follows the titular psychiatrist (Simon Pegg) as he searches the globe to discover the secret to true happiness. Rosamund Pike (Wrath of the Titans), and Christopher Plummer costar. Peter Chelsom (Shall We Dance, Serendipity) is directing from a script written by him, Maria von Heland (Big Girls Don’t Cry), and newcomer Tinker Lindsay.

• John Cusack is set to headline Airspace, a thriller about a pilot of a charter plane who finds his plane under attack by a MiG fighter jet. Roger Avary (The Rules of Attraction) is in talks to direct from a script penned by Briana Hartman (Brother’s Keeper). [Variety]

• Frank Langella (Robot and Frank, Frost/Nixon), Rosario Dawson (Eagle Eye), Josh Hartnett (30 Days of Night), and Gena Rowlands (The Notebook) will star in Parts Per Billion, an ensemble drama follows three couples as they weather a major devastating event. Brian Horiuchi is making his feature directing debut from his own script. [TheWrap]