Nagarjuna is busy working on the climax part of his ongoing flick Damarukam. Being directed by Srinivasa Reddy and produced by Venkat of RR Movie Makers, the film is the first-ever socio-fantasy of the actor and is costliest as well. The makers have put the budget at `35 crore and are presently erecting a huge set in about seven acres at Annapurna Studios. Bangalore beauty Anushka Shetty is romancing the Akkineni scion for fourth time. The duo paired with each other earlier in Super, Don and Ragada. Model-actor Ganesh Venkatraman who sizzled in Aakasamantha is doing a significant role in it. Devi Sri Prasad is composing the tunes.