NEW YORK (AP) _ Even a star like Sigourney Weaver can act like a fan.

``The most embarrassing moment of my life was ... I saw someone who looked a lot like Tom Cruise buying something,'' she told ABC's ``PrimeTime Thursday,'' which airs Thursday night.

So she let out a scream.

``And he turned around and it was Tom Cruise. And I was already known then. I mean I had made a film.''

And she screamed again.

``I ran out. I was so embarrassed,'' said Weaver, who starred as Ripley in the four ``Alien'' movies. Her latest films are ``Company Man,'' now in theaters, and ``Heartbreakers,'' which opens Friday.