diff --git a/localtime.go b/localtime.go
index 5a91bd6..30a31dc 100644
--- a/localtime.go
+++ b/localtime.go
@@ -97,7 +97,7 @@ func (d LocalDateTime) AsTime(zone *time.Location) time.Time {
 
 // String returns RFC 3339 representation of d.
 func (d LocalDateTime) String() string {
-	return d.LocalDate.String() + " " + d.LocalTime.String()
+	return d.LocalDate.String() + "T" + d.LocalTime.String()
 }
 
 // MarshalText returns RFC 3339 representation of d.
diff --git a/localtime_test.go b/localtime_test.go
index d972e5d..d8e255e 100644
--- a/localtime_test.go
+++ b/localtime_test.go
@@ -88,7 +88,7 @@ func TestLocalDateTime_String(t *testing.T) {
 		toml.LocalDate{2021, 6, 8},
 		toml.LocalTime{20, 12, 1, 2, 9},
 	}
-	require.Equal(t, "2021-06-08 20:12:01.000000002", d.String())
+	require.Equal(t, "2021-06-08T20:12:01.000000002", d.String())
 }
 
 func TestLocalDateTime_MarshalText(t *testing.T) {
@@ -98,7 +98,7 @@ func TestLocalDateTime_MarshalText(t *testing.T) {
 	}
 	b, err := d.MarshalText()
 	require.NoError(t, err)
-	require.Equal(t, []byte("2021-06-08 20:12:01.000000002"), b)
+	require.Equal(t, []byte("2021-06-08T20:12:01.000000002"), b)
 }
 
 func TestLocalDateTime_UnmarshalMarshalText(t *testing.T) {
diff --git a/toml_testgen_test.go b/toml_testgen_test.go
index d6ebdee..d4bf4da 100644
--- a/toml_testgen_test.go
+++ b/toml_testgen_test.go
@@ -1107,7 +1107,6 @@ func TestTOMLTest_Valid_Datetime_LocalTime(t *testing.T) {
 }
 
 func TestTOMLTest_Valid_Datetime_Local(t *testing.T) {
-	t.Skip("FIXME")
 	input := "local = 1987-07-05T17:45:00\nmilli = 1977-12-21T10:32:00.555\nspace = 1987-07-05 17:45:00\n"
 	jsonRef := "{\n  \"local\": {\n    \"type\": \"datetime-local\",\n    \"value\": \"1987-07-05T17:45:00\"\n  },\n  \"milli\": {\n    \"type\": \"datetime-local\",\n    \"value\": \"1977-12-21T10:32:00.555\"\n  },\n  \"space\": {\n    \"type\": \"datetime-local\",\n    \"value\": \"1987-07-05T17:45:00\"\n  }\n}\n"
 	testgenValid(t, input, jsonRef)