diff --git a/installers/charm/prometheus/src/charm.py b/installers/charm/prometheus/src/charm.py
index 3dcb5d4..e79de69 100755
--- a/installers/charm/prometheus/src/charm.py
+++ b/installers/charm/prometheus/src/charm.py
@@ -60,7 +60,7 @@
     ingress_whitelist_source_range: Optional[str]
     tls_secret_name: Optional[str]
     enable_web_admin_api: bool
-    image_pull_policy: Optional[str]
+    image_pull_policy: str
 
     @validator("web_subpath")
     def validate_web_subpath(cls, v):