Michael Strahan -- Knife-Wielding Nut Threatens to Kill Talk Show Host

A homeless man went to ABC studios in NYC Tuesday with a knife and threatened to kill Michael Strahan ... NYPD officials confirm to TMZ.

Andre Johnson appeared Tuesday AM at the Times Square studio where "Good Morning America" is shot. The 25-year-old man showed up at around 8:00 AM ... when the cast often walks out onto the sidewalk set to interact with onlookers.

Police say Johnson got into an argument with security, pulled a knife and said he was there to kill Strahan -- who makes appearances on "GMA" in addition to hosting "LIVE! With Kelly and Michael."

A cop working security then subdued Johnson and secured the knife.

The NY Post -- which broke the story -- says the man was charged with felony attempted assault as well as menacing and criminal possession of a weapon. It appears he's being held without bail.

TMZ caught up with Strahan's fiancee, Nicole Murphy, at LAX to talk about the incident.