Mourinho is the London club's most successful manager of all time, winning three Premier League titles over two spells in charge, and retains a good relationship with the Chelsea fans.
But while he admits that he is unsure what kind of reception he will get from the Blues' faithful, his main concern is to get the job done for United.
"To say I care is not true because, to be honest, when I go to a football match, I do not focus on that. I focus on the game, I try to prepare myself for matches, so I cannot say that I care," he told reporters.
"What can I expect? I don't know. They can think about me and remember our great relationship and have a good reaction. They can look at me and say 'for 90 minutes he is Man Utd manager and he's playing against us so he is not somebody we like in this moment'."
