Error: formControlName must be used with a parent formGroup directive. You'll want to add a formGroup directive - Angular reactive forms

I have the following template. I'm trying to get to grips with reactive forms but am having a problem.





First Name*









Then in my component I have:
@Component({
selector: 'guest-input',
templateUrl: './guest-input.component.html',
})
export class GuestInputComponent implements OnInit {
@Input()
guest: Guest;

guestForm: FormGroup;

constructor(private _fb: FormBuilder) { }

ngOnInit() {
this.guestForm = this._fb.group({
firstname: ['test', [Validators.required, Validators.minLength(3)]]
});
}
}



This all looks fine to me but for some reason I am getting:



Error: Uncaught (in promise): Error: formControlName must be used with a parent formGroup directive. You'll want to add a formGroup
directive and pass it an existing FormGroup instance (you can create one in your class).



I thought I had declared this in my .