There are talks of father-son duo Rishi and Ranbir Kapoor`s sharing of screen space in a film, but the actors have already shot for a commercial together. The television ad of cola brand Pepsi will see Rishi and Ranbir together for the first time. Sources from the sets reveal that both were comfortable during the shoot as they had to only play father-and-son in the commercial, which will go on air Sep 15. `Wake Up Sid` director Ayan Mukherji has also directed a teaser to the TVC that goes on air Monday, said a statement. The teaser concept revolves around a father dismissing his son?s chances of becoming a Crorepati while the son has a plan in place. The teaser ends with the theme music for "Kaun Banega Crorepati" -- whether the son becomes a Crorepati by participating in the show or by drinking Pepsi that remains to be seen.