diff --git a/config/config.go b/config/config.go
index 937726b7..860ac734 100644
--- a/config/config.go
+++ b/config/config.go
@@ -150,14 +150,14 @@ func (sc *SafeConfig) ReloadConfig(confFile string, logger log.Logger) (err erro
 // CelProgram encapsulates a cel.Program and makes it YAML marshalable.
 type CelProgram struct {
 	cel.Program
-	expression string
+	Expression string
 }
 
 // NewCelProgram creates a new CEL Program and returns an error if the
 // passed-in CEL expression does not compile.
 func NewCelProgram(s string) (CelProgram, error) {
 	program := CelProgram{
-		expression: s,
+		Expression: s,
 	}
 
 	env, err := cel.NewEnv(
@@ -200,8 +200,8 @@ func (c *CelProgram) UnmarshalYAML(unmarshal func(interface{}) error) error {
 
 // MarshalYAML implements the yaml.Marshaler interface.
 func (c CelProgram) MarshalYAML() (interface{}, error) {
-	if c.expression != "" {
-		return c.expression, nil
+	if c.Expression != "" {
+		return c.Expression, nil
 	}
 	return nil, nil
 }
diff --git a/prober/http.go b/prober/http.go
index 0cc83e93..cd09af94 100644
--- a/prober/http.go
+++ b/prober/http.go
@@ -95,7 +95,7 @@ func matchCelExpressions(ctx context.Context, reader io.Reader, httpConfig confi
 			return false
 		}
 		if result.Type() == cel.BoolType && result.Value().(bool) {
-			level.Error(logger).Log("msg", "Body matched CEL expression", "expression", httpConfig.FailIfBodyJSONMatchesCel)
+			level.Error(logger).Log("msg", "Body matched CEL expression", "expression", httpConfig.FailIfBodyJSONMatchesCel.Expression)
 			return false
 		}
 	}
@@ -111,7 +111,7 @@ func matchCelExpressions(ctx context.Context, reader io.Reader, httpConfig confi
 			return false
 		}
 		if result.Type() == cel.BoolType && !result.Value().(bool) {
-			level.Error(logger).Log("msg", "Body did not match CEL expression", "expression", httpConfig.FailIfBodyJSONNotMatchesCel)
+			level.Error(logger).Log("msg", "Body did not match CEL expression", "expression", httpConfig.FailIfBodyJSONNotMatchesCel.Expression)
 			return false
 		}
 	}