diff --git a/mllib/src/main/scala/org/apache/spark/mllib/util/MLUtils.scala b/mllib/src/main/scala/org/apache/spark/mllib/util/MLUtils.scala
index 4b9d77949f375..774170ff401e9 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/util/MLUtils.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/util/MLUtils.scala
@@ -120,7 +120,7 @@ object MLUtils {
       i += 1
     }
 
-    (label, indices, values)
+    (label, indices.toArray, values.toArray)
   }
 
   /**