EXCLUSIVE

Legendary actor Alan Arkin suffered a stroke ... TMZ has learned.

The actor, who starred in "Little Miss Sunshine," "Argo," "The Russians are Coming," "Grosse Pointe Blank," "Edward Scissorhands" and "Glengarry Glen Ross" had what his people called a "mini stroke" Monday and was hospitalized and released Tuesday.

We're told doctors did a battery of tests and there's no significant damage.