Post Malone has become so synonymous with the Dallas Cowboys -- he's now joined the famed "88 Club" group text that includes Drew Pearson, Michael Irvin, Dez Bryant and CeeDee Lamb!!!
Pearson revealed the eyebrow-raising fact to TMZ Sports this week ... saying Post has demonstrated so much love to Dallas over the past few years that he and other Cowboys legends have now opened their arms -- and their text messages -- to the "Congratulations" crooner.
It's, of course, a huge deal .