updated 11/10/2012 AT 1:50 PM ET
•originally published 11/10/2012 AT 5:00 PM ET
Weight-wise, Matthew McConaughey is at his lowest point.
The actor, 43, was snapped looking shockingly frail Friday as he caught a flight from Los Angeles to New Orleans, where The Dallas Buyer’s Club is set to begin filming Sunday.
“Matthew starts shooting this weekend, so he’s at his absolute lowest weight,” a source close to the actor tells PEOPLE. “In a month, he’ll begin to put it back on.”
Reporting by ELIZABETH LEONARD