Southern superstar Nagarjuna is all set to share the screen space with Amitabh Bachchan after two decades for an advertisement and says it's always a learning experience to work with the Bollywood megastar.

Both will be seen together in a commercial for Kalyan Jewellers.

"I am working with Amitabh after a long time. It's always a learning experience to work with him. He is very encouraging. There is so much to learn from him, ` Nagarjuna told reporters here.

The 53-year-old last worked with Big B, 70, in 1992 released film `Khuda Gawah` and recalling those days, he said: "We had shot the film in Nepal and it was a wonderful experience and it's been 20 years for that."