Alan Rickman’s portrayal of Severus Snape in the “Harry Potter” films is unforgettable, but in the newly released personal letters from Rickman, he didn’t always love the part.

The letters, part of the actor’s personal collection, will be auctioned off two years after his death and detail his “frustrations” with playing the iconic character.

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One letter included in the collection is from “Chamber of Secrets” producer David Heyman who wrote Rickman thanking him for his work.

“Thank you for making HP2 a success,” the letter reads. “I know, at times, you are frustrated but please know that you are an integral part of the films. And you are brilliant.”

Later, in 2009, Rickman titled a letter “Inside Snape’s Head”, which expressed concerns surrounding “Half-Blood Prince” director David Yates.

“It’s as if David Yates has decided that this is not important in the scheme of things i.e. teen audience appeal,” he said of his director, who helmed a number of films in the series.

Other letters included in the collection come from “Harry Potter” writer J.K. Rowling, Nicole Kidman, and a young Daniel Radcliffe.

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Rickman’s personal “Die Hard”, “Truly Madly Deeply” and “Robin Hood: Prince Of Thieves” scripts are also included.