In the letter, Coogler said that he "moved to tears" that people of various ethnic backgrounds supported the film and lauded the film's primarily black cast.
Fans took to the letter and flooded social media with their loving messages for the 31-year-old director.
One user wrote, "We don't deserve Ryan Coogler but glad he's here to share his brilliance".
Another user praised the director and wrote, "I studied film and theater for years and I don't have the words for what this film means to me. Thank you Mr. Coogler for showing the world how beautiful being Black can be???. #WakandaForever #RepresentationMatters #BlackPanther".
One tweeted, "Dear Ryan Coogler, You literally created a major event in the human timeline on this Earth. There will now be a BBP (Before Black Panther) and an ABP (After Black Panther) & for that all the Black people on this planet say: THANK U! Also, the Ancestors forever like..."
Another user thanked him for making "this amazing film".
The Marvel film director released the letter on Tuesday, outpouring his feelings and thankfulness in words.
The letter read, "I am struggling to find the words to express my gratitude at this moment, but I will try.
"Filmmaking is a team sport. And our team was made up [of] amazing people from all over the world who believed in this story. Deep down we all hoped that people would come to see a film about a fictional country on the continent of Africa, made up of a cast of people of African descent.
"Never in a million years did we imagine that you all would come out this strong. It still humbles me to think that people care enough to spend their money and time watching our film- But to see people of all backgrounds wearing clothing that celebrates their heritage, taking pictures next to our posters with their friends and family, and sometimes dancing in the lobbies of theaters- often moved me and my wife to tears.
"For the people who bought out theaters, who posted on social about how lit the film would be, bragged about our awesome cast, picked out outfits to wear, and who stood in line in theaters all over the world- all before seeing the film.
"To the press who wrote about the film for folks who hadn't yet seen it, and encouraged audiences to come out.
"And to the young ones, who came out with their parents, with their mentors, and with their friends.
"Thank you for giving our team of filmmakers the greatest gift: The opportunity to share this film, that we poured our hearts and souls into, with you" and signed it with his name and a hashtag #WakandaForever.
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The Marvel film is having a historic run at the box office and is already being hailed as a consequential cultural asset, all thanks to its African-theme and diverse, black cast.