diff --git a/http-client/src/main/java/io/micronaut/http/client/interceptor/HttpClientIntroductionAdvice.java b/http-client/src/main/java/io/micronaut/http/client/interceptor/HttpClientIntroductionAdvice.java
index <HASH>..<HASH> 100644
--- a/http-client/src/main/java/io/micronaut/http/client/interceptor/HttpClientIntroductionAdvice.java
+++ b/http-client/src/main/java/io/micronaut/http/client/interceptor/HttpClientIntroductionAdvice.java
@@ -185,9 +185,11 @@ public class HttpClientIntroductionAdvice implements MethodInterceptor<Object, O
                     String headerValue = header.value();
                     headers.put(headerName, headerValue);
                 }
-            } else {
-                Header header = context.getAnnotation(Header.class);
-                headers.put(header.name(), header.value());
+            }
+
+            Header headerAnnotation = context.getAnnotation(Header.class);
+            if (headerAnnotation != null) {
+                headers.put(headerAnnotation.name(), headerAnnotation.value());
             }
 
             List<NettyCookie> cookies = new ArrayList<>();
Handle header only if the Header annotation is present