diff --git a/Library/Homebrew/macos.rb b/Library/Homebrew/macos.rb
index 06215114cc..91c2050e8a 100644
--- a/Library/Homebrew/macos.rb
+++ b/Library/Homebrew/macos.rb
@@ -20,7 +20,7 @@ module MacOS extend self
   end
 
   def pretty_name
-    cat.to_s.split('_').map(&:capitalize).join(' ')
+    MacOS.version.pretty_name
   end
 
   def locate tool
diff --git a/Library/Homebrew/os/mac/version.rb b/Library/Homebrew/os/mac/version.rb
index c86974d768..c48b07eb62 100644
--- a/Library/Homebrew/os/mac/version.rb
+++ b/Library/Homebrew/os/mac/version.rb
@@ -13,5 +13,9 @@ module MacOS
           end
       super(Version.new(v))
     end
+
+    def pretty_name
+      @version.split('_').map(&:capitalize).join(' ')
+    end
   end
 end