The Austria international has been a long-term target for Real and his father, George, over the weekend further talked up their interest.
Alaba Snr said: "Everyone knows that Real Madrid is really interested in David, but for the moment we cannot say anything.
"Let's see what will happen this summer. This is not the time to talk about the teams that interest him. The interest of Madrid is already known to everyone, it is not a secret. But now, there is nothing to say.
"You will have to wait until the end of the season to see."