The Premier League leaders travel to Old Trafford unbeaten this season, but Van Gaal
believes that an "iron shield" makes him immune to his former assistant's tactics.
The Guardian quotes him as saying: "I'm [made] from a little bit of iron – so [I have] a shield, an iron shield.
"Maybe now you know that I am always a controversial person and a lot of media has written about that.
"We hardly speak to each other [at the moment]. Sometimes we SMS but when we see each other we feel the warmth between us and our families so that's nice. He is an a very modest and emotional human being."
Mourinho was part of Van Gaal's backroom staff during the Dutchman's reign at Barcelona.