Alan Rickman: Emma Thompson, J.K. Rowling and Others React to Actor's Death "This is hard to write," she said.

 -- "Harry Potter" and "Die Hard" actor Alan Rickman has died at the age of 69, his rep confirmed to ABC News.

The death came as a shock to many, who took to Twitter and social media to pay their respects to the acclaimed star.

Actress Emma Thompson, who co-starred with Rickman in "Love Actually," among other projects, released a heartfelt statement about her "ultimate ally."

"Alan was my friend and so this is hard to write because I have just kissed him goodbye," Thompson wrote. "What I remember most in this moment of painful leave-taking is his humor, intelligence, wisdom and kindness. His capacity to fell you with a look or lift you with a word. The intransigence which made him the great artist he was—his ineffable and cynical wit, the clarity with which he saw most things, including me, and the fact that he never spared me the view. I learned a lot from him," she said.

"He was the finest of actors and directors. I couldn’t wait to see what he was going to do with his face next," Thompson continued. "I consider myself hugely privileged to have worked with him so many times and to have been directed by him. He was the ultimate ally. In life, art and politics. I trusted him absolutely. He was, above all things, a rare and unique human being and we shall not see his like again."

Some of Rickman's other co-stars reacted to the news on Twitter, including James and Oliver Phelps, who played Fred and George Weasley in the "Potter" series. Matthew Lewis, who played Neville Longbottom in the films, wrote that Rickman "inspired my career more than he ever knew and I'll miss him."

British celebrities such as Stephen Fry, Harry Styles and Boy George also took to social media to pay their respects.

Here is what other stars and organizations had to say about his death.