diff --git a/CHANGELOG.md b/CHANGELOG.md
index 303a52b1..6937fd82 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,8 @@
 * fix: mapping to object extending `stdClass` to property with no setter.
 * feat: `stdClass` to `stdClass` mapping should work correctly.
 * feat: Mapping to existing values in a dynamic property.
+* perf(`ObjectToObjectTransformer`): Prevent delegating to `MainTransformer` if
+  the current value in a dynamic property is a scalar.
 
 ## 1.0.0
 
diff --git a/src/Transformer/Implementation/ObjectToObjectTransformer.php b/src/Transformer/Implementation/ObjectToObjectTransformer.php
index ff9aaf6b..8bd70c57 100644
--- a/src/Transformer/Implementation/ObjectToObjectTransformer.php
+++ b/src/Transformer/Implementation/ObjectToObjectTransformer.php
@@ -587,7 +587,10 @@ private function mapDynamicProperties(
                     }
 
 
-                    if ($currentTargetPropertyValue === null) {
+                    if (
+                        $currentTargetPropertyValue === null
+                        || is_scalar($currentTargetPropertyValue)
+                    ) {
                         /** @psalm-suppress MixedAssignment */
                         $targetPropertyValue = $sourcePropertyValue;
                     } else {