Varun spoke about it at the launch of the "Jee karda..." song from the film "Badlapur" here Thursday.
When asked to share his experience of working with Nawazuddin, Varun said: "I've learnt a lot from him about cinema and about how he conducts himself as a human being."
"I've to say that what I've realised about Nawaz is that he is one actor who runs away from fame. Nawaz is not only a gem of an actor, he is a gem of a human being.
"I'm very grateful to him that he is part of our film. This film would be incomplete with Nawaz as he is a very important part of it," he added.
In "Badlapur", Varun will be seen donning a rugged look for an aggressive character. The film also stars Yami Gautam, Huma Qureshi in key roles and it will hit screens Feb 20.