diff --git a/Gemfile b/Gemfile
index 520c052b..25069bd4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,7 @@ gemspec
 
 # maintain compatibility against master
 gem 'haml', github: 'haml/haml'
+gem 'faml', github: 'eagletmt/faml', branch: 'optional-extend', submodules: true
 
 gem 'benchmark-ips', '2.3.0'
 gem 'lineprof'
diff --git a/hamlit.gemspec b/hamlit.gemspec
index 6dcfa484..4c3322bf 100644
--- a/hamlit.gemspec
+++ b/hamlit.gemspec
@@ -25,8 +25,6 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency 'bundler', '~> 1.10'
   spec.add_development_dependency 'coffee-script'
-  spec.add_development_dependency 'faml', '>= 0.3.3'
-  spec.add_development_dependency 'haml'
   spec.add_development_dependency 'less'
   spec.add_development_dependency 'minitest-reporters', '~> 1.1'
   spec.add_development_dependency 'rails', '>= 4.0.0'