diff --git a/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/vector/VectorSimilarityFunction.java b/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/vector/VectorSimilarityFunction.java
index 69dcaa17368dc..af1b9382d7adf 100644
--- a/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/vector/VectorSimilarityFunction.java
+++ b/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/vector/VectorSimilarityFunction.java
@@ -116,7 +116,7 @@ public Block eval(Page page) {
                             }
                         }
                         if (dimensions == 0) {
-                            return context.blockFactory().newConstantFloatBlockWith(0F, 0);
+                            return context.blockFactory().newConstantNullBlock(positionCount);
                         }
 
                         float[] leftScratch = new float[dimensions];