Actor Sharad Kelkar, who will be seen in Ashutosh Gowariker's upcoming adventure-romance "Mohenjo Daro", has praised his co-star Hrithik Roshan by saying that he is very hard working.Asked how was it working with Hrithik, Sharad told IANS over phone: "He is very sweet and is always there to help you. He is very hardworking, everyone should learn from him on how much hard work he puts in (to his work)."The 39-year-old star also shared that the "Bang Bang!" star has a never to give up attitude. "Despite all the injuries, he got up and started shooting again. He has a never to give up attitude," Sharad added.Written and produced by Gowariker, the epic adventure-romance is set in the city of Mohenjo Daro in the era of the Indus Valley civilisation which dates back to 2,600 BC."Mohenjo Daro", which also marks the debut of actress Pooja Hegde, is all set to hit the screens on August 12.