Chennai, Jan 24 (IANS): Actor Dhanush says debutant Akshara Haasan has the most challenging role in their forthcoming film "Shamitabh", but she has pulled it off convincingly because acting is in her blood.

"Of all the roles, Akshara has the most challenging part in the film. I don't think she ever struggled to pull it off as acting runs in her blood," Dhanush told IANS.

Akshara is the daughter of veteran actors Kamal Haasan and Sarika.

"Shamitabh", slated for release Feb 6, also stars megastar Amitabh Bachchan, and it is directed by R. Balakrishnan.

On working with Big B, Dhanush said: "I never expected I'd get an opportunity to work with him. There's nothing more to add when you're working with a legend because everything is so special."

Dhanush along with Balki and Akshara were in the city Friday to promote their film. They interacted with the students of Sathyabama University.

In the film, Big B has given voice to Dhanush's character.