Mumbai, Dec 9 (IANS) One thing that can be said for sure about Bollywood superstar Amitabh Bachchan's films with Rani Mukerji is that they project the actors in very unusual, exceedingly unconventional combinations.

In Sanjay Leela Bhansali's "Black" they played the amazingly unorthodox teacher and pupil. And in Karan Johar's "Kabhi Alvida Naa Kehna" (KANT) Big B was the philandering Sexy Sam who tells his daughter-in-law to leave his son, so he can find love.

Now in Ravi Chopra's just released "Baabul", Big B and Rani play the protagonists, a father-in-law determined to get his widowed daughter-in-law remarried.

So pivotal are the two characters that Hema Malini, who plays Big B's wife, confesses she has relatively little to do.

Speaking on his acutely striking bonding with Rani, Big B told IANS: "We've been cast in very unusual roles in 'Black'. And then in KANK we were a very different kind of father-in-law and daughter-in-law.

"Now we play another very different and unusual father-in-law and daughter-in-law in 'Baabul'. I guess we're lucky to have our acting talents being tested in such unusual ways. I'm very fortunate to get such unusual opportunities.

"Rani is a terrific co-star and it's a pleasure to work with her. All of us - Jaya, Abhishek and I - are very fond of her."

He recalls Rani's concern for his health on the sets. "She's a very caring girl. And a thorough professional on camera."

Big B is hoping "Baabul" would have the same social impact as Chopra's earlier "Baghban".

"Though it has in-sync sound, it needed some dubbing, I think it has turned out to be a film that reclaims many of our basic values like 'Vivah', which I thought was a very sweet film.