The former Spurs winger is expected to complete a return to north London this week in a sensational loan deal from the Spanish champions.
It appears that the move is all but complete, but Mourinho is not willing to tempt fate and would not elaborate on the forthcoming arrival of Bale.
The Portuguese manager was talking after Spurs scraped through the Europa League second qualifying round on Thursday, coming from behind to claim a 2-1 win over Lokomotiv Plovdiv, who were down to nine men.
‘I cannot comment, I don’t comment on something that I don’t know,’ Mourinho told reporters in Bulgaria.
‘For me, at this moment, until I’m told Gareth Bale is a Tottenham player, I still think and feel and respect the fact that he’s a Real Madrid player, so I’m not going to comment on a Real Madrid player.’
It was last season’s star signing who proved the hero on Thursday in Bulgaria as Tanguy Ndombele scored the winning goal with just five minutes to spare.
The Frenchman had a very slow start to life at Spurs last campaign, but Mourinho now feels he is ready to come good.
‘Tanguy is in a process of evolution,’ said the manager. ‘Last season he wasn’t. Last season he stuck in a situation where I couldn’t see evolution. In this moment he’s training very, very well.
‘He’s recovering from his injury, he’s recovering physically and today he gave us what we needed in this last 30 minutes.
‘In this moment, I believe in Tanguy. I never doubted his quality. Never. I doubted in some moments his motivation and commitment and professional attitude.
‘In this moment I believe in him. Today we made this decision together to not start the game because he also feels that he needs a bit more but in this moment I think that Tanguy can do well for us.’