diff --git a/lib/mu-message-priority.cc b/lib/mu-message-priority.cc
index 3358614f..09dc2eef 100644
--- a/lib/mu-message-priority.cc
+++ b/lib/mu-message-priority.cc
@@ -25,7 +25,7 @@
 using namespace Mu;
 
 std::string
-to_string(MessagePriority prio)
+Mu::to_string(MessagePriority prio)
 {
 	return std::string{message_priority_name(prio)};
 }