The Chelsea defender was playing at Aston Villa when the Portuguese manager won two EPL titles with the West London club.
But, despite playing against Mourinho’s Chelsea side on numerous occasions, Cahill admits he has never heard of the two time Champions League winner.
He said: “I have honestly don’t know who he is. Obviously, lots of the players and fans at the club talk about him, but it really doesn’t ring a bell.
“I hadn’t even heard of Real Madrid or the country of Spain. I didn’t even realise there were others countries or lives outside my own.”
These shocking statements will likely annoy Mourinho, who is a self-confessed ego-maniac. In fact, the ‘special one’ once sacked his 4-year-old daughter for simply asking what he did for a living.
The England centre-back has already been criticised for similar incidents in the past, most notably when he mistook fellow defender David Luiz for the Stamford Bridge tea lady.
But, accusations of being a giant baby aside, Cahill insists that he is enjoying his football at the moment.
He said: “I just head and kick the ball thing and people like me for it.”
A source within the club, revealed that the 27-year-old needs constant care and attention.
“Gary is like any other footballer at Chelsea. In fact, he’s one of the better behaved ones. He has never shagged or shot anyone while on the training facilities.”