David Thewlis, best known to American audiences for playing Remus Lupin in the Harry Potter movies, has joined the cast of Red 2, Summit/Lionsgate’s sequel to the hit 2012 action movie.

Bruce Willis, Helen Mirren and John Malkovich are back as over-the-hill special agents forced out of retirement, and the movie has added extra wattage in the form of Anthony Hopkins and Catherine Zeta-Jones, as well as Byun-Hun Lee. 

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Thewlis is playing a character called The Frog, an information dealer who got his name by poisoning the water supply at the Kremlin using a poisonous Amazonian frog.

Dean Parisot is directing the movie, due to start shooting later this fall in Montreal.

Lorenzo DiBonaventura and Mark Vahradian will produce the film via their DiBonaventura Pictures banner. The film is scheduled to be released on August 2, 2013.

Thewlis’ recent credits include Steven Spielberg’s War Horse and Luc Besson’s The Lady. He is repped by CAA and Ken McReddie Associates.