diff --git a/src/Collection.php b/src/Collection.php
index 055ade77a..c2f50d879 100644
--- a/src/Collection.php
+++ b/src/Collection.php
@@ -209,16 +209,16 @@ public function __toString(): string
      * Executes an aggregation framework pipeline on the collection.
      *
      * @see Aggregate::__construct() for supported options
-     * @param array $pipeline Aggregation pipeline
-     * @param array $options  Command options
+     * @param array|Pipeline $pipeline Aggregation pipeline
+     * @param array          $options  Command options
      * @throws UnexpectedValueException if the command response was malformed
      * @throws UnsupportedException if options are not supported by the selected server
      * @throws InvalidArgumentException for parameter/option parsing errors
      * @throws DriverRuntimeException for other driver errors (e.g. connection errors)
      */
-    public function aggregate(array $pipeline, array $options = []): CursorInterface
+    public function aggregate(array|Pipeline $pipeline, array $options = []): CursorInterface
     {
-        if (is_builder_pipeline($pipeline)) {
+        if (is_array($pipeline) && is_builder_pipeline($pipeline)) {
             $pipeline = new Pipeline(...$pipeline);
         }
 
@@ -1014,13 +1014,13 @@ public function updateSearchIndex(string $name, array|object $definition, array
      * Create a change stream for watching changes to the collection.
      *
      * @see Watch::__construct() for supported options
-     * @param array $pipeline Aggregation pipeline
-     * @param array $options  Command options
+     * @param array|Pipeline $pipeline Aggregation pipeline
+     * @param array          $options  Command options
      * @throws InvalidArgumentException for parameter/option parsing errors
      */
-    public function watch(array $pipeline = [], array $options = []): ChangeStream
+    public function watch(array|Pipeline $pipeline = [], array $options = []): ChangeStream
     {
-        if (is_builder_pipeline($pipeline)) {
+        if (is_array($pipeline) && is_builder_pipeline($pipeline)) {
             $pipeline = new Pipeline(...$pipeline);
         }
 
diff --git a/src/Database.php b/src/Database.php
index a3064ddd3..f27268c88 100644
--- a/src/Database.php
+++ b/src/Database.php
@@ -188,16 +188,16 @@ public function __toString(): string
      * and $listLocalSessions. Requires MongoDB >= 3.6
      *
      * @see Aggregate::__construct() for supported options
-     * @param array $pipeline Aggregation pipeline
-     * @param array $options  Command options
+     * @param array|Pipeline $pipeline Aggregation pipeline
+     * @param array          $options  Command options
      * @throws UnexpectedValueException if the command response was malformed
      * @throws UnsupportedException if options are not supported by the selected server
      * @throws InvalidArgumentException for parameter/option parsing errors
      * @throws DriverRuntimeException for other driver errors (e.g. connection errors)
      */
-    public function aggregate(array $pipeline, array $options = []): CursorInterface
+    public function aggregate(array|Pipeline $pipeline, array $options = []): CursorInterface
     {
-        if (is_builder_pipeline($pipeline)) {
+        if (is_array($pipeline) && is_builder_pipeline($pipeline)) {
             $pipeline = new Pipeline(...$pipeline);
         }
 
@@ -582,13 +582,13 @@ public function selectGridFSBucket(array $options = []): Bucket
      * Create a change stream for watching changes to the database.
      *
      * @see Watch::__construct() for supported options
-     * @param array $pipeline Aggregation pipeline
-     * @param array $options  Command options
+     * @param array|Pipeline $pipeline Aggregation pipeline
+     * @param array          $options  Command options
      * @throws InvalidArgumentException for parameter/option parsing errors
      */
-    public function watch(array $pipeline = [], array $options = []): ChangeStream
+    public function watch(array|Pipeline $pipeline = [], array $options = []): ChangeStream
     {
-        if (is_builder_pipeline($pipeline)) {
+        if (is_array($pipeline) && is_builder_pipeline($pipeline)) {
             $pipeline = new Pipeline(...$pipeline);
         }
 
diff --git a/tests/Collection/BuilderCollectionFunctionalTest.php b/tests/Collection/BuilderCollectionFunctionalTest.php
index 2ace15109..c974ac40d 100644
--- a/tests/Collection/BuilderCollectionFunctionalTest.php
+++ b/tests/Collection/BuilderCollectionFunctionalTest.php
@@ -6,6 +6,7 @@
 use MongoDB\Builder\Pipeline;
 use MongoDB\Builder\Query;
 use MongoDB\Builder\Stage;
+use PHPUnit\Framework\Attributes\TestWith;
 
 use function iterator_to_array;
 
@@ -18,7 +19,9 @@ public function setUp(): void
         $this->collection->insertMany([['x' => 1], ['x' => 2], ['x' => 2]]);
     }
 
-    public function testAggregate(): void
+    #[TestWith([true])]
+    #[TestWith([false])]
+    public function testAggregate(bool $pipelineAsArray): void
     {
         $this->collection->insertMany([['x' => 10], ['x' => 10], ['x' => 10]]);
         $pipeline = new Pipeline(
@@ -27,8 +30,10 @@ public function testAggregate(): void
                 buckets: 2,
             ),
         );
-        // Extract the list of stages for arg type restriction
-        $pipeline = iterator_to_array($pipeline);
+
+        if ($pipelineAsArray) {
+            $pipeline = iterator_to_array($pipeline);
+        }
 
         $results = $this->collection->aggregate($pipeline)->toArray();
         $this->assertCount(2, $results);
@@ -257,7 +262,9 @@ public function testUpdateManyWithPipeline(): void
         $this->assertEquals(3, $result[0]->x);
     }
 
-    public function testWatch(): void
+    #[TestWith([true])]
+    #[TestWith([false])]
+    public function testWatch(bool $pipelineAsArray): void
     {
         $this->skipIfChangeStreamIsNotSupported();
 
@@ -268,8 +275,10 @@ public function testWatch(): void
         $pipeline = new Pipeline(
             Stage::match(operationType: Query::eq('insert')),
         );
-        // Extract the list of stages for arg type restriction
-        $pipeline = iterator_to_array($pipeline);
+
+        if ($pipelineAsArray) {
+            $pipeline = iterator_to_array($pipeline);
+        }
 
         $changeStream = $this->collection->watch($pipeline);
         $this->collection->insertOne(['x' => 3]);
diff --git a/tests/Database/BuilderDatabaseFunctionalTest.php b/tests/Database/BuilderDatabaseFunctionalTest.php
index 9b89d87e1..1df18dbb1 100644
--- a/tests/Database/BuilderDatabaseFunctionalTest.php
+++ b/tests/Database/BuilderDatabaseFunctionalTest.php
@@ -6,6 +6,7 @@
 use MongoDB\Builder\Pipeline;
 use MongoDB\Builder\Query;
 use MongoDB\Builder\Stage;
+use PHPUnit\Framework\Attributes\TestWith;
 
 use function iterator_to_array;
 
@@ -18,7 +19,9 @@ public function tearDown(): void
         parent::tearDown();
     }
 
-    public function testAggregate(): void
+    #[TestWith([true])]
+    #[TestWith([false])]
+    public function testAggregate(bool $pipelineAsArray): void
     {
         $this->skipIfServerVersion('<', '6.0.0', '$documents stage is not supported');
 
@@ -33,14 +36,18 @@ public function testAggregate(): void
                 buckets: 2,
             ),
         );
-        // Extract the list of stages for arg type restriction
-        $pipeline = iterator_to_array($pipeline);
+
+        if ($pipelineAsArray) {
+            $pipeline = iterator_to_array($pipeline);
+        }
 
         $results = $this->database->aggregate($pipeline)->toArray();
         $this->assertCount(2, $results);
     }
 
-    public function testWatch(): void
+    #[TestWith([true])]
+    #[TestWith([false])]
+    public function testWatch(bool $pipelineAsArray): void
     {
         $this->skipIfChangeStreamIsNotSupported();
 
@@ -51,8 +58,10 @@ public function testWatch(): void
         $pipeline = new Pipeline(
             Stage::match(operationType: Query::eq('insert')),
         );
-        // Extract the list of stages for arg type restriction
-        $pipeline = iterator_to_array($pipeline);
+
+        if ($pipelineAsArray) {
+            $pipeline = iterator_to_array($pipeline);
+        }
 
         $changeStream = $this->database->watch($pipeline);
         $this->database->selectCollection($this->getCollectionName())->insertOne(['x' => 3]);