The actor plays an old man with grey hair in the commercial for a mobile phone company.
Basu told Mumbai Mirror: "I was at the airport when I first caught a glimpse of Ranbir and that too on mute. I was shocked. I thought someone had put Barfee's first look out there without my knowledge!
"I caught the complete ad later and was taken aback with what I saw. Ranbir's getup in the TV ad is almost identical to that of his old-age look in Barfee. I was disappointed.
"But I have also shot several TV commercials with Ranbir in the past and I know that he sticks to the brief that he is given, without asking any questions.
"What can I say and what can I do? We had really taken a lot of pain to guard his look and keep it under wraps. But I guess it had to happen this way. So it's fine now."
Kapoor has previously appeared in a Pepsi advertisement with his veteran actor father Rishi Kapoor.
In November, it was rumoured that Kapoor was fattening up for his role in Basu's romantic comedy