Unity MissingComponentException: There is no 'GameObject' attached to the “BG” game object, but a script is trying to access it

У меня есть GameObject BG , хочу что бы при изменении Toggle он отключался.

    private GameObject BG;
// Use this for initialization
void Start () {
    BG = GetComponent<GameObject>();
}
// Update is called once per frame
void Update () {
}
public void SetTheme(bool newValue)
{
    BG.SetActive(!BG.activeSelf);
}

Но этот код не работает. Дает такую ошибку:

MissingComponentException: There is no 'GameObject' attached to the "BG" game object, but a script is trying to access it. You probably need to add a GameObject to the game object "BG". Or your script needs to check if the component is attached before using it.

Хотя в проекте есть Panel BG