With Food & Liquor II: The Great American Rap Album Pt. 1 arriving this week, it comes as no surprise that Lupe Fiasco is busy on the promotion side of things. Case in point, Lupe teamed up with Australian singer Guy Sebastian to perform their joint single "Battle Scars" live on The Late Show with David Letterman. Backed up with a live band, both artists made sure to deliver an energetic set. In case you missed it, read our review of Food & Liquor II: The Great American Rap Album Pt. 1 here.