diff --git a/logp/logptest/logger.go b/logp/logptest/logger.go
index 8ee002c..74803cc 100644
--- a/logp/logptest/logger.go
+++ b/logp/logptest/logger.go
@@ -60,7 +60,12 @@ type Logger struct {
 // replacement for a *logp.Logger, or the logger can be accessed via
 // [Logger.Logger]
 func NewFileLogger(t testing.TB, dir string) *Logger {
-	encoderConfig := ecszap.ECSCompatibleEncoderConfig(zapcore.EncoderConfig{})
+	encoderConfig := ecszap.ECSCompatibleEncoderConfig(zapcore.EncoderConfig{
+		// As long as NameKey is NOT EMPTY it will be overridden
+		// by the correct key. So we set it to 'enabled' to make it very
+		// clear this is NOT the final key for the logger name.
+		NameKey: "enabled",
+	})
 	encoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
 	encoder := zapcore.NewJSONEncoder(encoderConfig)
 
diff --git a/logp/logptest/logger_test.go b/logp/logptest/logger_test.go
index 321fc19..72d9957 100644
--- a/logp/logptest/logger_test.go
+++ b/logp/logptest/logger_test.go
@@ -33,6 +33,7 @@ import (
 
 func TestNewFileLogger(t *testing.T) {
 	logger := NewFileLogger(t, "")
+	logger.Logger = logger.Named("test-logger")
 	logger.Debug("foo")
 
 	assertLogFormat(t, logger.logFile.Name())
@@ -93,6 +94,7 @@ func assertLogFormat(t *testing.T, path string) {
 		entry := struct {
 			Timestamp string `json:"@timestamp"`
 			LogLevel  string `json:"log.level"`
+			Logger    string `json:"log.logger"`
 			Message   string `json:"message"`
 		}{}
 
@@ -112,6 +114,10 @@ func assertLogFormat(t *testing.T, path string) {
 		if entry.Message == "" {
 			t.Error("message cannot be empty")
 		}
+
+		if entry.Logger == "" {
+			t.Error("'log.logger' cannot be empty")
+		}
 	}
 }