diff --git a/pyhelm3/models.py b/pyhelm3/models.py
index d03fdc6..2142eed 100644
--- a/pyhelm3/models.py
+++ b/pyhelm3/models.py
@@ -14,6 +14,7 @@
     FilePath,
     AnyUrl as PydanticAnyUrl,
     HttpUrl as PydanticHttpUrl,
+    UrlConstraints,
     constr,
     field_validator
 )
@@ -61,10 +62,13 @@ def validate_str_as(validate_type):
     adapter = TypeAdapter(validate_type)
     return lambda v: str(adapter.validate_python(v))
 
+class PydanticDataUrl(PydanticAnyUrl):
+    _constraints = UrlConstraints(allowed_schemes=["data"])
 
 #: Annotated string types for URLs
 AnyUrl = t.Annotated[str, AfterValidator(validate_str_as(PydanticAnyUrl))]
 HttpUrl = t.Annotated[str, AfterValidator(validate_str_as(PydanticHttpUrl))]
+DataUrl = t.Annotated[str, AfterValidator(validate_str_as(PydanticDataUrl))]
 
 
 class ChartDependency(BaseModel):
@@ -173,7 +177,7 @@ class ChartMetadata(BaseModel):
         default_factory = list,
         description = "List of maintainers for the chart."
     )
-    icon: t.Optional[HttpUrl] = Field(
+    icon: t.Optional[HttpUrl | DataUrl] = Field(
         None,
         description = "URL to an SVG or PNG image to be used as an icon."
     )