who are the main start actors in this film?
Daniel Radcliffe, Rupert Grint, and Emma Watson are the three leading characters.
Harry Potter (film series)
The series was mainly produced by David Heyman, and stars Daniel Radcliffe, Rupert Grint, and Emma Watson as the three leading characters: Harry Potter, Ron Weasley, and Hermione Granger. 
who played professor sybil trelawney in harry potter Emma Thompson. who is the aforementioned person? She is a British actress, screenwriter, activist, author and comedian. were her parents actors too? Yes. what are their names? Eric Thompson and Phyllida Law when she(mentioned at the beginning) came to prominence as an artist? 1987 in two BBC TV series. what are the series that she performed in that period? "There's Nothing To Worry About!", "The Crystal Cube", "Saturday Night Fry", among others. what are some of her notable films? "Harry Potter" film series (2004–2011), "Wit" (2001), "Love Actually" (2003) and many more. what is the first mentioned film series about? It is a film series based on the eponymous novels by author J. K. Rowling.
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Harry Potter (film series) [SEP] Introduction
Four directors worked on the series: Chris Columbus, Alfonso Cuarón, Mike Newell, and David Yates. Michael Goldenberg wrote the screenplay for "Harry Potter and the Order of the Phoenix" (2007), while the remaining films' screenplays were written by Steve Kloves. Production took place over ten years, with the main story arc following Harry's quest to overcome his arch-enemy Lord Voldemort. "Harry Potter and the Deathly Hallows", the seventh and final novel in the series, was adapted into two feature-length parts. "Part 1" was released in November 2010, and "Part 2" was released in July 2011.