diff --git a/lib/Differentiator/VisitorBase.cpp b/lib/Differentiator/VisitorBase.cpp
index 20e18795b..87c55b4cd 100644
--- a/lib/Differentiator/VisitorBase.cpp
+++ b/lib/Differentiator/VisitorBase.cpp
@@ -916,7 +916,8 @@ namespace clad {
 
     // Account for the this pointer.
     if (isa<CXXMethodDecl>(m_DiffReq.Function) &&
-        !utils::IsStaticMethod(m_DiffReq.Function))
+        !utils::IsStaticMethod(m_DiffReq.Function) &&
+        (!m_DiffReq.Functor || m_DiffReq.Mode != DiffMode::jacobian))
       ++numOfDerivativeParams;
     // All output parameters will be of type `void*`. These
     // parameters will be casted to correct type before the call to the actual