NullReferenceException in 20 says " Object Reference not set to instance of object Please help

using UnityEngine;
using System.Collections;

public class PlayerDeath : MonoBehaviour {
	
	public GameManager TheGameManager;

	void Start () {
	TheGameManager = GetComponent<GameManager> ();
	}
	
	// Update is called once per frame
	void Update () {
	
	}

	void OnTriggerEnter2D(Collider2D other){
		if(other.name == "Player")
		{
			TheGameManager.RespawnPlayer();
		}
	}
}

Do you have TheGameManager component on the same object? GetComponent() gets from the same gameobject this script is attached to.