diff --git a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregator.java b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregator.java
index 9a33085760c..cf930bc3bec 100644
--- a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregator.java
+++ b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregator.java
@@ -112,7 +112,7 @@ public class SketchAggregator implements Aggregator
     } else if (update instanceof byte[]) {
       union.update((byte[]) update);
     } else if (update instanceof Double) {
-      union.update(((Double) update));
+      union.update((Double) update);
     } else if (update instanceof Integer || update instanceof Long) {
       union.update(((Number) update).longValue());
     } else if (update instanceof int[]) {
diff --git a/extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregationTest.java b/extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregationTest.java
index fe3077b38f4..06e62876c6f 100644
--- a/extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregationTest.java
+++ b/extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregationTest.java
@@ -529,6 +529,21 @@ public class SketchAggregationTest
     Assert.assertEquals(2, ((SketchHolder) agg.get()).getSketch().getEstimate(), 0);
   }
 
+  @Test
+  public void testUpdateUnionWithDouble()
+  {
+    Double[] columnValues = new Double[]{2.0};
+    final TestObjectColumnSelector selector = new TestObjectColumnSelector(columnValues);
+    final Aggregator agg = new SketchAggregator(selector, 4096);
+    agg.aggregate();
+    Assert.assertFalse(agg.isNull());
+    Assert.assertNotNull(agg.get());
+    Assert.assertTrue(agg.get() instanceof SketchHolder);
+    Assert.assertEquals(1, ((SketchHolder) agg.get()).getEstimate(), 0);
+    Assert.assertNotNull(((SketchHolder) agg.get()).getSketch());
+    Assert.assertEquals(1, ((SketchHolder) agg.get()).getSketch().getEstimate(), 0);
+  }
+
   private void assertPostAggregatorSerde(PostAggregator agg) throws Exception
   {
     Assert.assertEquals(