Geisel married the writer, whose real name was Theodor Geisel, in 1968. After his death in 1991, she founded Dr Seuss Enterprises to license the characters he created and protect their use outside of his books.

Audrey Geisel served as an executive producer on film adaptations of Dr Seuss books including the current hit, “The Grinch,” which has earned more than US$380 million at global box offices since its release in theatres last month.

Talent and literary agency ICM Partners, which represents Dr Seuss Enterprises, confirmed that Audrey Geisel died on Wednesday. No cause of death was revealed.

“Audrey lived a life of extraordinary philanthropy and was the artistic and entrepreneurial force behind Dr Seuss Enterprises,” ICM said in a statement. “Her creativity and devotion to her husband’s work are indelibly linked with his legacy.”

Dr Seuss wrote and illustrated more than 45 books, including “The Cat in the Hat,” “Green Eggs and Ham” and “How the Grinch Stole Christmas” before his death at the age of 87.