diff --git a/demo/hello.ts b/demo/hello.ts
index 574e54745..b804642df 100644
--- a/demo/hello.ts
+++ b/demo/hello.ts
@@ -360,12 +360,20 @@ export class HelloApp {
         },
       },
       {
-        key: 'nested.arrays.0',
+        key: 'nested.arrays.0.item',
+        type: 'input',
+        templateOptions: {
+          label: 'Array with dots',
+        },
+        defaultValue: 'Default Value A',
+        parsers: [(value) => (value || '').toUpperCase()],
+      }, {
+        key: 'nested.arrays[1].item',
         type: 'input',
         templateOptions: {
           label: 'Array property',
         },
-        defaultValue: 'Default Value',
+        defaultValue: 'Default Value B',
         parsers: [(value) => (value || '').toUpperCase()],
       }, {
         type: 'repeatSection',
@@ -433,11 +441,6 @@ export class HelloApp {
         sports: false,
         languages: true,
       },
-      nested: {
-        property: {
-          magic: 'Nested property Content',
-        },
-      },
       investments: [
         {
           investmentName: 'Formly',
diff --git a/src/core/services/formly.form.builder.ts b/src/core/services/formly.form.builder.ts
index 273d7b3e7..0ec6b50e4 100644
--- a/src/core/services/formly.form.builder.ts
+++ b/src/core/services/formly.form.builder.ts
@@ -3,6 +3,7 @@ import { FormGroup, FormArray, FormControl, AbstractControl, Validators } from '
 import { FormlyConfig } from './formly.config';
 import { evalStringExpression, evalExpressionValueSetter, evalExpression, getFieldId, assignModelValue, isObject } from './../utils';
 import { FormlyFieldConfig } from '../components/formly.field.config';
+import { getKeyPath } from '../utils';
 
 @Injectable()
 export class FormlyFormBuilder {
@@ -49,17 +50,17 @@ export class FormlyFormBuilder {
           if (field.defaultValue) {
             this.defaultPath = path;
           }
-          path = path.split('.');
+          path = getKeyPath({key: field.key});
         }
 
         if (path.length > 1) {
           const rootPath = path.shift();
-          let nestedForm = <FormGroup>(form.get(rootPath) ? form.get(rootPath) : new FormGroup({}, field.validators ? field.validators.validation : undefined, field.asyncValidators ? field.asyncValidators.validation : undefined));
-          if (!form.get(rootPath)) {
+          let nestedForm = <FormGroup>(form.get(rootPath.toString()) ? form.get(rootPath.toString()) : new FormGroup({}, field.validators ? field.validators.validation : undefined, field.asyncValidators ? field.asyncValidators.validation : undefined));
+          if (!form.get(rootPath.toString())) {
             form.addControl(rootPath, nestedForm);
           }
           if (!model[rootPath]) {
-            model[rootPath] = isNaN(rootPath) ? {} : [];
+            model[rootPath] = isNaN(path[0]) ? {} : [];
           }
 
           const originalKey = field.key;
@@ -71,7 +72,7 @@ export class FormlyFormBuilder {
           this.formlyConfig.getMergedField(field);
           this.addFormControl(form, field, model[path[0]] || field.defaultValue || '');
           if (field.defaultValue && !model[path[0]]) {
-            let path = this.defaultPath.split('.');
+            let path: any = getKeyPath({key: this.defaultPath});
             path = path.pop();
             assignModelValue(this.model, path, field.defaultValue);
             this.defaultPath = undefined;
diff --git a/src/core/utils.ts b/src/core/utils.ts
index 9adedac9b..8a1f69c49 100644
--- a/src/core/utils.ts
+++ b/src/core/utils.ts
@@ -66,7 +66,7 @@ export function getFieldModel(model: any, field: FormlyFieldConfig, constructEmp
 
 export function assignModelValue(model, path, value) {
   if (typeof path === 'string') {
-    path = path.split('.');
+    path = getKeyPath({key: path});
   }
 
   if (path.length > 1) {
@@ -82,7 +82,7 @@ export function assignModelValue(model, path, value) {
 
 export function getValueForKey(model, path) {
   if (typeof path === 'string') {
-    path = path.split('.');
+    path = getKeyPath({key: path});
   }
   if (path.length > 1) {
     const e = path.shift();