diff --git a/installers/charm/prometheus/config.yaml b/installers/charm/prometheus/config.yaml
index a5f5e8a..c1c0fb9 100644
--- a/installers/charm/prometheus/config.yaml
+++ b/installers/charm/prometheus/config.yaml
@@ -35,6 +35,11 @@
       of Keystone, it may need to be configured to handle the requested size.
       Note: if set to 0, there is no limit.
     default: 0
+  ingress_class:
+    type: string
+    description: |
+      Ingress class name. This is useful for selecting the ingress to be used
+      in case there are multiple ingresses in the underlying k8s clusters.
   ingress_whitelist_source_range:
     type: string
     description: |
diff --git a/installers/charm/prometheus/src/charm.py b/installers/charm/prometheus/src/charm.py
index cf4f956..e3e0e42 100755
--- a/installers/charm/prometheus/src/charm.py
+++ b/installers/charm/prometheus/src/charm.py
@@ -56,6 +56,7 @@
     max_file_size: int
     site_url: Optional[str]
     cluster_issuer: Optional[str]
+    ingress_class: Optional[str]
     ingress_whitelist_source_range: Optional[str]
     tls_secret_name: Optional[str]
     enable_web_admin_api: bool
@@ -196,9 +197,10 @@
                     str(config.max_file_size) + "m"
                     if config.max_file_size > 0
                     else config.max_file_size
-                ),
-                "kubernetes.io/ingress.class": "public",
+                )
             }
+            if config.ingress_class:
+                annotations["kubernetes.io/ingress.class"] = config.ingress_class
             ingress_resource_builder = IngressResourceV3Builder(
                 f"{self.app.name}-ingress", annotations
             )