diff --git a/installers/charm/prometheus/src/charm.py b/installers/charm/prometheus/src/charm.py
index 5fdee72..cf4f956 100755
--- a/installers/charm/prometheus/src/charm.py
+++ b/installers/charm/prometheus/src/charm.py
@@ -197,6 +197,7 @@
                     if config.max_file_size > 0
                     else config.max_file_size
                 ),
+                "kubernetes.io/ingress.class": "public",
             }
             ingress_resource_builder = IngressResourceV3Builder(
                 f"{self.app.name}-ingress", annotations