diff --git a/hmp-commands.hx b/hmp-commands.hx
index 3a4ae39..8939b98 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1008,6 +1008,21 @@ Set the parameter @var{parameter} for migration.
 ETEXI
 
     {
+        .name       = "migrate_start_postcopy",
+        .args_type  = "",
+        .params     = "",
+        .help       = "Switch migration to postcopy mode",
+        .mhandler.cmd = hmp_migrate_start_postcopy,
+    },
+
+STEXI
+@item migrate_start_postcopy
+@findex migrate_start_postcopy
+Switch in-progress migration to postcopy mode. Ignored after the end of
+migration (or once already in postcopy).
+ETEXI
+
+    {
         .name       = "client_migrate_info",
         .args_type  = "protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
         .params     = "protocol hostname port tls-port cert-subject",
diff --git a/hmp.c b/hmp.c
index 3f807b7..38dd8f7 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1272,6 +1272,13 @@ void hmp_client_migrate_info(Monitor *mon, const QDict *qdict)
     hmp_handle_error(mon, &err);
 }
 
+void hmp_migrate_start_postcopy(Monitor *mon, const QDict *qdict)
+{
+    Error *err = NULL;
+    qmp_migrate_start_postcopy(&err);
+    hmp_handle_error(mon, &err);
+}
+
 void hmp_set_password(Monitor *mon, const QDict *qdict)
 {
     const char *protocol  = qdict_get_str(qdict, "protocol");
diff --git a/hmp.h b/hmp.h
index 81656c3..a8c5b5a 100644
--- a/hmp.h
+++ b/hmp.h
@@ -69,6 +69,7 @@ void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict);
 void hmp_client_migrate_info(Monitor *mon, const QDict *qdict);
+void hmp_migrate_start_postcopy(Monitor *mon, const QDict *qdict);
 void hmp_set_password(Monitor *mon, const QDict *qdict);
 void hmp_expire_password(Monitor *mon, const QDict *qdict);
 void hmp_eject(Monitor *mon, const QDict *qdict);
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 2e9fa3c..2176666 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -127,6 +127,9 @@ struct MigrationState
     int64_t xbzrle_cache_size;
     int64_t setup_time;
     int64_t dirty_sync_count;
+
+    /* Flag set once the migration has been asked to enter postcopy */
+    bool start_postcopy;
 };
 
 void process_incoming_migration(QEMUFile *f);
diff --git a/migration/migration.c b/migration/migration.c
index 6989e21..5ee2c11 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -616,6 +616,28 @@ void qmp_migrate_set_parameters(bool has_compress_level,
     }
 }
 
+void qmp_migrate_start_postcopy(Error **errp)
+{
+    MigrationState *s = migrate_get_current();
+
+    if (!migrate_postcopy_ram()) {
+        error_setg(errp, "Enable postcopy with migration_set_capability before"
+                         " the start of migration");
+        return;
+    }
+
+    if (s->state == MIGRATION_STATUS_NONE) {
+        error_setg(errp, "Postcopy must be started after migration has been"
+                         " started");
+        return;
+    }
+    /*
+     * we don't error if migration has finished since that would be racy
+     * with issuing this command.
+     */
+    atomic_set(&s->start_postcopy, true);
+}
+
 /* shared migration helpers */
 
 static void migrate_set_state(MigrationState *s, int old_state, int new_state)
diff --git a/qapi-schema.json b/qapi-schema.json
index c6f1942..48644f5 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -670,6 +670,14 @@
             '*tls-port': 'int', '*cert-subject': 'str' } }
 
 ##
+# @migrate-start-postcopy
+#
+# Switch migration to postcopy mode
+#
+# Since: 2.4
+{ 'command': 'migrate-start-postcopy' }
+
+##
 # @MouseInfo:
 #
 # Information about a mouse device.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index d2ba800..6d8547a 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -718,6 +718,25 @@ Example:
 
 EQMP
     {
+        .name       = "migrate-start-postcopy",
+        .args_type  = "",
+        .mhandler.cmd_new = qmp_marshal_migrate_start_postcopy,
+    },
+
+SQMP
+migrate-start-postcopy
+----------------------
+
+Switch an in-progress migration to postcopy mode. Ignored after the end of
+migration (or once already in postcopy).
+
+Example:
+-> { "execute": "migrate-start-postcopy" }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "query-migrate-cache-size",
         .args_type  = "",
         .mhandler.cmd_new = qmp_marshal_query_migrate_cache_size,
