The vivacious Natassha who has become a regular in Ektaa Kapoor's banner will be seen playing the role of an unwed single mother in Balaji's forthcoming film "Koi Aap Sa".

"I found it to be one of the most challenging roles in my career so far," Natassha reveals, adding that she even watched a few of Preity Zinta's films to prepare for the role, reports Bollywood Trade.

"Preity is a brilliant actress. I saw a couple of her films to get a feel of the mannerisms. However, the role that I play is not a very bold one," she says.

"Koi Aap Sa" tells the story of two friends, Natassha and Aftab who stand by each other through thick and thin. Natassha is playing the role of a tomboyish and bubbly girl in the first half, after which her character takes a serious turn. Himanshu Mallik is the love interest of Natassha in the film.

This is Natassha's third film with Ekta Kapoor, the earlier two being "Kucch To Hai" and "Krishna Cottage".

"It is more like family working with Ektaa," says the actress who's known to be a hot favourite the TV producer