diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 54215cf88d7550d687e1d5428dc075bb756689b8..862ff201debb18f7bb80294445a20a6ab1443931 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -174,8 +174,6 @@ def sum(*args)
       # association, it will be used for the query. Otherwise, construct options and pass them with
       # scope to the target class's +count+.
       def count(column_name = nil, count_options = {})
-        return 0 if owner.new_record?
-
         column_name, count_options = nil, column_name if column_name.is_a?(Hash)
 
         if options[:counter_sql] || options[:finder_sql]
@@ -366,6 +364,16 @@ def add_to_target(record)
         record
       end
 
+      def scope(opts = {})
+        scope = super()
+        scope.none! if opts.fetch(:nullify, true) && null_scope?
+        scope
+      end
+
+      def null_scope?
+        owner.new_record? && !foreign_key_present?
+      end
+
       private
 
         def custom_counter_sql
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 536e108f0ed7874dcff67fb692b66e3f1663b46b..50f9fca7c086a053ec033a3672dfac3c99247952 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -31,7 +31,7 @@ class CollectionProxy < Relation
       def initialize(association) #:nodoc:
         @association = association
         super association.klass, association.klass.arel_table
-        merge! association.scope
+        merge! association.scope(nullify: false)
       end
 
       def target
@@ -835,9 +835,8 @@ def scoping
       # Returns a <tt>Relation</tt> object for the records in this association
       def scope
         association = @association
-        scope = @association.scope
-        scope.none! if @association.owner.new_record?
-        scope.extending! do
+
+        @association.scope.extending! do
           define_method(:proxy_association) { association }
         end
       end
diff --git a/activerecord/lib/active_record/null_relation.rb b/activerecord/lib/active_record/null_relation.rb
index 4c1c91e3dff156f21c89eea74a4327d3dcc76043..f8f7a6c9769618179a2b5b31f5828abccc1139ae 100644
--- a/activerecord/lib/active_record/null_relation.rb
+++ b/activerecord/lib/active_record/null_relation.rb
@@ -46,7 +46,7 @@ def where_values_hash
       {}
     end
 
-    def count
+    def count(*)
       0
     end