diff --git a/temporal/error.go b/temporal/error.go
index 7801e2250..b3aba9d0c 100644
--- a/temporal/error.go
+++ b/temporal/error.go
@@ -210,12 +210,12 @@ func IsApplicationError(err error) bool {
 	return errors.As(err, &applicationError)
 }
 
-// IsWorkflowExecutionAlreadyStartedError return if the err is a
-// WorkflowExecutionAlreadyStartedError or if an error in the chain is a
-// ChildWorkflowExecutionAlreadyStartedError.
+// IsWorkflowExecutionAlreadyStartedError returns true if an error in the chain
+// is a WorkflowExecutionAlreadyStartedError or ChildWorkflowExecutionAlreadyStartedError.
 func IsWorkflowExecutionAlreadyStartedError(err error) bool {
-	if _, ok := err.(*serviceerror.WorkflowExecutionAlreadyStarted); ok {
-		return ok
+	var alreadyStartedError *serviceerror.WorkflowExecutionAlreadyStarted
+	if errors.As(err, &alreadyStartedError) {
+		return true
 	}
 	var childError *ChildWorkflowExecutionAlreadyStartedError
 	return errors.As(err, &childError)