diff --git a/datafusion/functions/src/datetime/now.rs b/datafusion/functions/src/datetime/now.rs
index b2221215b94b..74eb5aea4255 100644
--- a/datafusion/functions/src/datetime/now.rs
+++ b/datafusion/functions/src/datetime/now.rs
@@ -21,7 +21,7 @@ use arrow::datatypes::DataType;
 use arrow::datatypes::DataType::Timestamp;
 use arrow::datatypes::TimeUnit::Nanosecond;
 
-use datafusion_common::{internal_err, Result, ScalarValue};
+use datafusion_common::{internal_err, ExprSchema, Result, ScalarValue};
 use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyInfo};
 use datafusion_expr::{ColumnarValue, Expr, ScalarUDFImpl, Signature, Volatility};
 
@@ -84,4 +84,8 @@ impl ScalarUDFImpl for NowFunc {
             ScalarValue::TimestampNanosecond(now_ts, Some("+00:00".into())),
         )))
     }
+
+    fn is_nullable(&self, _args: &[Expr], _schema: &dyn ExprSchema) -> bool {
+        false
+    }
 }