AC Milan's general manager Adriano Galliani has said Berlusconi is in "great shape" after his heart operation.
Talking from a Lega Calcio meeting in Milan, Galliani revealed: "I spent a few hours with him in hospital on Monday night and I am very happy because I found him so well: strong and full of energy.
"It's quite extraordinary when you think that he was only operated on last Tuesday and I saw him on Monday.
"It's incredible in the space of only six days. I was there from 6pm to about 8pm and found him really in great shape: he's talking, making phone calls, he's doing a lot.
"I was so surprised to see him so active, he definitely doesn't look like someone who has just undergone an operation of this scale."
Galliani added that he believes Berlusconi, who will turn 80 in September, will be released from the San Raffaele hospital at some point next week.