diff --git a/lib/elasticsearch/dsl/search/queries/inner_hits.rb b/lib/elasticsearch/dsl/search/queries/inner_hits.rb
index c0ac470..4783dc7 100644
--- a/lib/elasticsearch/dsl/search/queries/inner_hits.rb
+++ b/lib/elasticsearch/dsl/search/queries/inner_hits.rb
@@ -104,6 +104,30 @@ def sort(*args, &block)
             end
           end
 
+          # Specify the _source on the inner_hits definition. By default inner_hits contain complete source.
+          #
+          # @example
+          #   inner_hits 'last_tweet' do
+          #     size 10
+          #     from 5
+          #     source ['likes']
+          #     sort do
+          #       by :date, order: 'desc'
+          #       by :likes, order: 'asc'
+          #     end
+          #   end
+          #
+          # @param [ Array, Hash ]
+          #
+          # @return self.
+          #
+          # @since 0.1.9
+          def _source(args)
+            @source = args
+            self
+          end
+          alias_method :source, :_source
+
           # Convert the definition to a hash, to be used in a search request.
           #
           # @example
@@ -124,6 +148,7 @@ def to_hash
             call
             @hash = @value
             @hash[:sort] = @sort.to_hash if @sort
+            @hash[:_source] = @source if defined?(@source)
             @hash
           end
         end
diff --git a/spec/elasticsearch/dsl/search/collapse_spec.rb b/spec/elasticsearch/dsl/search/collapse_spec.rb
index aee2943..d9146a5 100644
--- a/spec/elasticsearch/dsl/search/collapse_spec.rb
+++ b/spec/elasticsearch/dsl/search/collapse_spec.rb
@@ -61,6 +61,7 @@
         inner_hits 'last_tweet' do
           size 10
           from 5
+          _source ['date']
           sort do
             by :date, order: 'desc'
             by :likes, order: 'asc'
@@ -73,6 +74,7 @@
       { name: 'last_tweet',
         size: 10,
         from: 5,
+        _source: ['date'],
         sort: [ { date: { order: 'desc' } },
                 { likes: { order: 'asc' } } ]
       }
@@ -90,4 +92,4 @@
       expect(coll.to_hash[:inner_hits]).to eq(inner_hits_hash)
     end
   end
-end
\ No newline at end of file
+end
diff --git a/spec/elasticsearch/dsl/search/queries/inner_hits_spec.rb b/spec/elasticsearch/dsl/search/queries/inner_hits_spec.rb
index 0f5fb8f..0c5e125 100644
--- a/spec/elasticsearch/dsl/search/queries/inner_hits_spec.rb
+++ b/spec/elasticsearch/dsl/search/queries/inner_hits_spec.rb
@@ -83,6 +83,38 @@
                                             { likes: { order: 'asc' } }])
       end
     end
+
+    describe '#_source' do
+      context 'when excludes' do
+        before do
+          search._source({excludes: 'date'})
+        end
+
+        it 'applies the option' do
+          expect(search.to_hash[:_source][:excludes]).to eq('date')
+        end
+      end
+
+      context 'when includes' do
+        before do
+          search._source({includes: 'date'})
+        end
+
+        it 'applies the option' do
+          expect(search.to_hash[:_source][:includes]).to eq('date')
+        end
+      end
+
+      context 'when listing fields' do
+        before do
+          search._source(['last_tweet', 'date'])
+        end
+
+        it 'applies the option' do
+          expect(search.to_hash[:_source]).to eq(['last_tweet', 'date'])
+        end
+      end
+    end
   end
 
   describe '#initialize' do
diff --git a/spec/elasticsearch/dsl/search_spec.rb b/spec/elasticsearch/dsl/search_spec.rb
index 1b93836..c588dab 100644
--- a/spec/elasticsearch/dsl/search_spec.rb
+++ b/spec/elasticsearch/dsl/search_spec.rb
@@ -287,6 +287,7 @@ def bool_query(obj)
           inner_hits 'last_tweet' do
             size 10
             from 5
+            _source ['date']
             sort do
               by :date, order: 'desc'
               by :likes, order: 'asc'
@@ -300,6 +301,7 @@ def bool_query(obj)
       { name: 'last_tweet',
         size: 10,
         from: 5,
+        _source: ['date'],
         sort: [ { date: { order: 'desc' } },
                 { likes: { order: 'asc' } }]
       }
@@ -328,58 +330,4 @@ def bool_query(obj)
       expect(s.to_hash).to eq(expected_hash)
     end
   end
-
-  describe '#collapse' do
-
-    let(:s) do
-      search do
-        query do
-          match title: 'test'
-        end
-        collapse :user do
-          max_concurrent_group_searches 4
-          inner_hits 'last_tweet' do
-            size 10
-            from 5
-            sort do
-              by :date, order: 'desc'
-              by :likes, order: 'asc'
-            end
-          end
-        end
-      end
-    end
-
-    let(:inner_hits_hash) do
-      { name: 'last_tweet',
-        size: 10,
-        from: 5,
-        sort: [ { date: { order: 'desc' } },
-               { likes: { order: 'asc' } }]
-      }
-    end
-
-    let(:expected_hash) do
-      { query: { match: { title: 'test' } },
-        collapse: { field: :user,
-                    max_concurrent_group_searches: 4,
-                    inner_hits: inner_hits_hash }  }
-    end
-
-    it 'sets the field name' do
-      expect(s.to_hash[:collapse][:field]).to eq(:user)
-    end
-
-    it 'sets the max_concurrent_group_searches option' do
-      expect(s.to_hash[:collapse][:max_concurrent_group_searches]).to eq(4)
-    end
-
-    it 'sets the inner_hits' do
-      expect(s.to_hash[:collapse][:inner_hits]).to eq(inner_hits_hash)
-    end
-
-    it 'constructs the correct hash' do
-      expect(s.to_hash).to eq(expected_hash)
-    end
-  end
 end