diff --git a/src/propertywatchimpl.hpp b/src/propertywatchimpl.hpp
index 6e957ae..d0153e4 100644
--- a/src/propertywatchimpl.hpp
+++ b/src/propertywatchimpl.hpp
@@ -3,6 +3,7 @@
 #include <sdbusplus/message.hpp>
 #include <sdbusplus/bus/match.hpp>
 #include <vector>
+#include "callback.hpp"
 #include "data_types.hpp"
 #include "propertywatch.hpp"
 
@@ -141,6 +142,12 @@
         }
 
         std::get<2>(item->second).get() = p.second.template get<T>();
+
+        // Invoke callback if present.
+        if (this->alreadyRan && this->callback)
+        {
+            (*this->callback)();
+        }
     }
 }