Filmmaker R Balki says megastar Amitabh Bachchan, who won his fourth National award today for "Piku," is a stupendous performer.

Balki has worked with the 73-year-old actor in films including "Cheeni Kum," "Paa," "Shamitabh," and yet-to-be-released "Ki & Ka".

"I think nobody can be more proud of him (Amitabh Bachchan) more than me. Proud is an understatement. He deserves a lot more. He is a stupendous actor and far bigger than all of us," Balki told PTI.

In "Piku," the veteran actor played a hypochondriac father of an independent girl played by Deepika Padukone. Directed by Shoojit Sircar, the road drama also received award for best original screenplay and dialogue.

In "Ki & Ka," Bachchan makes a special appearance with his wife Jaya and according to the filmmaker it is the best role he has written for his favourite star.

"The role I have written for Amit ji in 'Ki & Ka' is the best for him so far. I have a great working relationship with him and I know how to bring the best out of him as an artist," he said.