diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 84ab9e62e7..21eae1975e 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1387,7 +1387,7 @@ public:
 	bool bang_trigger_at(int32_t route_index, int32_t row_index);
 	bool unbang_trigger_at(int32_t route_index, int32_t row_index);
 
-	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
+	PBD::Command* globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
 
 protected:
 	friend class AudioEngine;
diff --git a/libs/ardour/session_time.cc b/libs/ardour/session_time.cc
index b98d1d9d08..d81890a979 100644
--- a/libs/ardour/session_time.cc
+++ b/libs/ardour/session_time.cc
@@ -299,9 +299,11 @@ Session::any_duration_to_samples (samplepos_t position, AnyTime const & duration
 	return duration.samples;
 }
 
-void
+PBD::Command*
 Session::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
 {
+	PBD::Command* undo_command = new Temporal::TimeDomainCommand (from, to);
+
 	{
 		std::shared_ptr<RouteList const> rl (routes.reader());
 
@@ -312,4 +314,6 @@ Session::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeD
 
 	_playlists->globally_change_time_domain (from, to);
 	_locations->globally_change_time_domain (from, to);
+
+	return undo_command;
 }