Our research shows that Ayan Mukherji was part of a crowd scene in KANK. And Punit Malhotra was one of the cricket players in K3G.
Interestingly, KJo too started in a bit role in Aditya Chopra's DDLJ before he turned director. And now Parmeet Sethi, who also had a miniscule part in DDLJ, has directed a film for YRF. Hey, this 'extra' thing really works.