The first guest vocalist The Letter Black announced was rock and rap legend Trevor McNevan from Thousand Foot Krutch, FM Static, and I Am The Storm. The second guest vocalist they announced was Blake Whiteley, a solo rap/hip hop artist signed to True Breed Records (the hip-hop cousin of Rockfest Records, under the Nashville Label Group umbrella).
The Letter Black Announces Guests Vocalists for Upcoming Album
Rock On Purpose 