Fergie's obsession with Taco Bell could mean free food for you -- if the Black Eye'd Pea ever feels like runnin' for the border after a concert.

TMZ has obtained a letter written to The Dutchess by Greg Creed, President of Taco Bell, offering her an "ultimate after-party" at any local Taco Bell near a stop on her concert tour, where she and her fans can enjoy free Fourthmeals after the concert. All Ferg has to do is contact them a week in advance, and she and the crowd "will be served free Extreme Cheese and Beef Quesadillas for three hours" following one of her shows. Ay, ay, ay!