'90210' Star Matt Lanter Changes Flat Tire For Teenagers

"90210" hunk Matt Lanter nailed the role of a AAA tow truck driver by coming to the rescue of 2 teenage girls -- one of whom is hoping the run-in will be her big break in Hollywood.

The girls thought they were totally screwed when they got a flat in a Sherman Oaks, CA parking lot -- but Matt was Johnny-on-the-spot ... and offered to help fix the flat.

When it was all done, he gave one of them his manager's number when she slyly -- and wisely -- mentioned she's an aspiring actress. Her luck ran out when she asked Matt how she could get in touch with him.

All she got was his Snapchat info ... plus, the tire-change, of course.