diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7957a6d..3c6927c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Yii2 Active Record Save Relations Behavior Change Log
 
+## [1.5.2]
+### Fixed
+- Fix a regression in Has One saving introduced by #33 fix.
+
 ## [1.5.1]
 ### Fixed
 - Bug #33: Custom relation scenario was set too late and was preventing attributes from being correctly set (thx @phrakon)
diff --git a/src/SaveRelationsBehavior.php b/src/SaveRelationsBehavior.php
index 9063e66..75bebd9 100644
--- a/src/SaveRelationsBehavior.php
+++ b/src/SaveRelationsBehavior.php
@@ -296,16 +296,7 @@ class SaveRelationsBehavior extends Behavior
                 // If relation is has_one, try to set related model attributes
                 foreach ($this->_relations as $relationName) {
                     if (array_key_exists($relationName, $this->_oldRelationValue)) { // Relation was not set, do nothing...
-                        /** @var ActiveQuery $relation */
-                        $relation = $model->getRelation($relationName);
-                        if ($relation->multiple === false && !empty($model->{$relationName})) {
-                            Yii::debug("Setting foreign keys for {$relationName}", __METHOD__);
-                            foreach ($relation->link as $relatedAttribute => $modelAttribute) {
-                                if ($model->{$modelAttribute} !== $model->{$relationName}->{$relatedAttribute}) {
-                                    $model->{$modelAttribute} = $model->{$relationName}->{$relatedAttribute};
-                                }
-                            }
-                        }
+                        $this->_setRelationForeignKeys($relationName);
                     }
                 }
             }
@@ -384,9 +375,13 @@ class SaveRelationsBehavior extends Behavior
      */
     private function _prepareHasOneRelation(BaseActiveRecord $model, $relationName, ModelEvent $event)
     {
+        Yii::debug("_prepareHasOneRelation for {$relationName}", __METHOD__);
         $relationModel = $model->{$relationName};
         $this->validateRelationModel(self::prettyRelationName($relationName), $relationName, $model->{$relationName});
-        if ($relationModel->getIsNewRecord()) {
+        $relation = $model->getRelation($relationName);
+        $p1 = $model->isPrimaryKey(array_keys($relation->link));
+        $p2 = $relationModel::isPrimaryKey(array_values($relation->link));
+        if ($relationModel->getIsNewRecord() && $p1 && !$p2) {
             // Save Has one relation new record
             if ($event->isValid && (count($model->dirtyAttributes) || $model->{$relationName}->isNewRecord)) {
                 Yii::debug('Saving ' . self::prettyRelationName($relationName) . ' relation model', __METHOD__);
@@ -465,6 +460,29 @@ class SaveRelationsBehavior extends Behavior
     }
 
     /**
+     * Set relation foreign keys that point to owner primary key
+     * @param $relationName
+     */
+    protected function _setRelationForeignKeys($relationName)
+    {
+        /** @var BaseActiveRecord $owner */
+        $owner = $this->owner;
+        /** @var ActiveQuery $relation */
+        $relation = $owner->getRelation($relationName);
+        if ($relation->multiple === false && !empty($owner->{$relationName})) {
+            Yii::debug("Setting foreign keys for {$relationName}", __METHOD__);
+            foreach ($relation->link as $relatedAttribute => $modelAttribute) {
+                if ($owner->{$modelAttribute} !== $owner->{$relationName}->{$relatedAttribute}) {
+                    if ($owner->{$relationName}->isNewRecord) {
+                        $owner->{$relationName}->save();
+                    }
+                    $owner->{$modelAttribute} = $owner->{$relationName}->{$relatedAttribute};
+                }
+            }
+        }
+    }
+
+    /**
      * Link the related models.
      * If the models have not been changed, nothing will be done.
      * Related records will be linked to the owner model using the BaseActiveRecord `link()` method.
@@ -642,7 +660,6 @@ class SaveRelationsBehavior extends Behavior
     {
         /** @var BaseActiveRecord $owner */
         $owner = $this->owner;
-
         if ($this->_oldRelationValue[$relationName] !== $owner->{$relationName}) {
             if ($owner->{$relationName} instanceof BaseActiveRecord) {
                 $owner->link($relationName, $owner->{$relationName});
diff --git a/tests/SaveRelationsBehaviorTest.php b/tests/SaveRelationsBehaviorTest.php
index 42719d3..c2260b6 100644
--- a/tests/SaveRelationsBehaviorTest.php
+++ b/tests/SaveRelationsBehaviorTest.php
@@ -689,7 +689,7 @@ class SaveRelationsBehaviorTest extends \PHPUnit_Framework_TestCase
         $profile->loadRelations($data);
         $this->assertEquals('Someone Else', $profile->user->username, "User name should be 'Someone Else'");
         $this->assertTrue($profile->user->isNewRecord, "User should be a new record");
-        $profile->save();
+        $this->assertEquals(1, $profile->user_id);
         $this->assertTrue($profile->save(), 'Profile could not be saved');
         $this->assertEquals('Someone Else', $profile->user->username, "User name should be 'Someone Else'");
     }
diff --git a/tests/models/User.php b/tests/models/User.php
index e69912b..9372b12 100644
--- a/tests/models/User.php
+++ b/tests/models/User.php
@@ -3,9 +3,12 @@
 namespace tests\models;
 
 use lhs\Yii2SaveRelationsBehavior\SaveRelationsBehavior;
+use lhs\Yii2SaveRelationsBehavior\SaveRelationsTrait;
 
 class User extends \yii\db\ActiveRecord
 {
+    use SaveRelationsTrait;
+
     /**
      * @inheritdoc
      */