diff --git a/extensions/resteasy-reactive/rest-client-jaxrs/deployment/src/main/java/io/quarkus/jaxrs/client/reactive/deployment/JaxrsClientReactiveProcessor.java b/extensions/resteasy-reactive/rest-client-jaxrs/deployment/src/main/java/io/quarkus/jaxrs/client/reactive/deployment/JaxrsClientReactiveProcessor.java
index 24579bdde4a60..8bdb9b9878a33 100644
--- a/extensions/resteasy-reactive/rest-client-jaxrs/deployment/src/main/java/io/quarkus/jaxrs/client/reactive/deployment/JaxrsClientReactiveProcessor.java
+++ b/extensions/resteasy-reactive/rest-client-jaxrs/deployment/src/main/java/io/quarkus/jaxrs/client/reactive/deployment/JaxrsClientReactiveProcessor.java
@@ -1964,7 +1964,7 @@ private void addInputStream(BytecodeCreator methodCreator, AssignableResultHandl
                 methodCreator.invokeVirtualMethod(MethodDescriptor.ofMethod(ClientMultipartForm.class, "entity",
                         ClientMultipartForm.class, String.class, String.class, Object.class, String.class, Class.class),
                         multipartForm, formParamResult, partFilenameResult, fieldValue,
-                        methodCreator.load(partType),
+                        methodCreator.load(partType != null ? partType : MediaType.APPLICATION_OCTET_STREAM),
                         // FIXME: doesn't support generics
                         methodCreator.loadClassFromTCCL(type)));
     }
diff --git a/extensions/resteasy-reactive/rest-client/deployment/src/test/java/io/quarkus/rest/client/reactive/multipart/MultipartFilenameTest.java b/extensions/resteasy-reactive/rest-client/deployment/src/test/java/io/quarkus/rest/client/reactive/multipart/MultipartFilenameTest.java
index 69bec01287d09..f345586162509 100644
--- a/extensions/resteasy-reactive/rest-client/deployment/src/test/java/io/quarkus/rest/client/reactive/multipart/MultipartFilenameTest.java
+++ b/extensions/resteasy-reactive/rest-client/deployment/src/test/java/io/quarkus/rest/client/reactive/multipart/MultipartFilenameTest.java
@@ -401,7 +401,6 @@ public static class ClientFormUsingByteArray {
 
     public static class ClientFormUsingInputStream {
         @FormParam("myFile")
-        @PartType(APPLICATION_OCTET_STREAM)
         @PartFilename(FILE_NAME)
         public InputStream file;
     }