"American Pie" star Eddie Kaye Thomas -- who played Finch in the movies -- just called the police, claiming a female houseguest threatened to kill him with a knife ... law enforcement sources tell TMZ ... and now a SWAT team is outside his house.
According to sources, the couple got into an argument and the woman grabbed a kitchen knife and threatened him ... so Thomas ran outside and call 911.
A SWAT team has responded to the Hollywood Hills home, where the woman remains barricaded inside.
UPDATE: The standoff is now over. The woman is currently in police custody.