diff --git a/lib/github_changelog_generator/generator/generator_generation.rb b/lib/github_changelog_generator/generator/generator_generation.rb
index a86bf89..c642766 100644
--- a/lib/github_changelog_generator/generator/generator_generation.rb
+++ b/lib/github_changelog_generator/generator/generator_generation.rb
@@ -21,7 +21,8 @@ module GitHubChangelogGenerator
 
       log += File.read(options[:base]) if File.file?(options[:base])
 
-      log += "\n\n\\* *This Change Log was automatically generated by [github_changelog_generator](https://github.com/skywinder/Github-Changelog-Generator)*"
+      credit_line = "\* *This Change Log was automatically generated by [github_changelog_generator](https://github.com/skywinder/Github-Changelog-Generator)*"
+      log += "\n\n\#{credit_line}" if log.include? credit_line == false
       @log = log
     end