Angular 2: how do I get some data from nested json objects?

I want to show the street of a person. But it didn't work with the code that I have. I think I do it wrong. (to get the name of a person works perfectly) json file:

{
  "id":1,
  "name": "someName",
  "address":{
      "street":"someStreet",
      "number":"10"
  }
}

service get json:

 public getPerson(id:string):Observable<Person> {
               return this.http.get(PersonService.PATH + id + '.json')
                  .map((res:Response) => res.json());
        }

typescript file PersonDetail:

@Component({
    selector: "person",
    template: `
        <h3>Detail of {{person.name}}</h3> --> this works
        <p>{{person.address.street}}</p> --> this not
                  `
})
export class PersonDetail {
    private person:Person = Person.createEmptyPerson();
    private router:Router;

    constructor(personService:PersonService, params:RouteParams, router:Router) {
        personService.getItem(params.get("id")).subscribe((person:Person) => {
            this.person =person;
        });
        this.router = router;
    }
}

Person:

import {Address} from "./address";
export class Person {
    id:number;
    name:string;
   adress:Address;


    constructor(id:number, name:string, adress:Address) {
        this.id = id;
        this.name = name;
        this.adress = adress;
    }


    public static createEmptyPerson():Person{
        return new Person(0, "",null);
    }

}

Addres:

export class Address {
    street:string;
    number:number;


    constructor(street:string, number:number) {
        this.street = street;
        this.number = number;
    }

    public static createEmptyAddress():Address {
        return new Address("",0);
    }

}