diff --git a/prometheus_client/exposition.py b/prometheus_client/exposition.py
index 8c84ffb5..100e8e2b 100644
--- a/prometheus_client/exposition.py
+++ b/prometheus_client/exposition.py
@@ -446,12 +446,21 @@ def factory(cls, registry: CollectorRegistry) -> type:
         return MyMetricsHandler
 
 
-def write_to_textfile(path: str, registry: CollectorRegistry, escaping: str = openmetrics.ALLOWUTF8) -> None:
+def write_to_textfile(path: str, registry: CollectorRegistry, escaping: str = openmetrics.ALLOWUTF8, tmpdir: Optional[str] = None) -> None:
     """Write metrics to the given path.
 
     This is intended for use with the Node exporter textfile collector.
-    The path must end in .prom for the textfile collector to process it."""
-    tmppath = f'{path}.{os.getpid()}.{threading.current_thread().ident}'
+    The path must end in .prom for the textfile collector to process it.
+
+    An optional tmpdir parameter can be set to determine where the
+    metrics will be temporarily written to. If not set, it will be in
+    the same directory as the .prom file. If provided, the path MUST be
+    on the same filesystem."""
+    if tmpdir is not None:
+        filename = os.path.basename(path)
+        tmppath = f'{os.path.join(tmpdir, filename)}.{os.getpid()}.{threading.current_thread().ident}'
+    else:
+        tmppath = f'{path}.{os.getpid()}.{threading.current_thread().ident}'
     try:
         with open(tmppath, 'wb') as f:
             f.write(generate_latest(registry, escaping))