Kuch Na Kaho Rohan Sippy carries directorial baton while father Ramesh plays the watchful producer and pushes for perfection.

"I got to know Dad better after working with him."

Twenty-eight years later, as he plays the toe-tapping music of his first film, Kuch Na Kaho, Rohan does not betray the nervousness of a man working in the shadow of a legend. It could be because the man sitting outside his office, in casual blue jeans and sneakers, is a calming influence, a point of reference as well as a good friend. Ramesh Sippy, his father and producer of the soon-to-be-released Kuch Na Kaho, was his "entry ticket to Mumbai films", says Rohan. And Rohan, who has grown up, literally, with cinema around him-he lives in a building which is partly rented out to the Central Board of Film Certification-would not have it any other way.

Father, son, co-worker. In Bollywood where dynasties flow thicker than blood, working with Dad is a rite of passage, like being pushed into the first acting course or acquiring the first Land Cruiser. Everybody does it, whether it is Qayamat director Harry Baweja, who gift-wrapped an acting course at the Lee Strasberg Theatre Institute in Los Angeles for his son Harman, or Rakesh Roshan, who could only think of his son when it came to casting Kaho Na ... Pyaar Hai and now, the forthcoming Koi ... Mil Gaya.

As he sits on the mixing table, the monitor freezing an image of the three-foot animatronic alien of Koi ... Mil Gaya, Roshan looks every glowing inch the doting dad. "After Kaho Na in 2000, I did 80 per cent work on a script, but I was not happy with it," he says, twisting one of the three Om rings on his fingers. "Then one night, the idea of Koi ... Mil Gaya came to me. I woke up at 6.30 a.m., spoke to Hrithik who was shooting for Yaadein in the UK and told him the story. He said I must do it." The collaboration was perfect, sometimes almost wordless. "He had to play a very difficult character. For three-fourths of the film, he is autistic," he says, relating with dutiful pride how Hrithik walked into his bedroom one day, in character-he had put on spectacles, changed his hairstyle and was wearing oversize shirts.

Koi ... Mil Gaya Rakesh Roshan directs his son as an autistic boy who is transformed by his friendship with an alien.

"Hrithik has done his job, I have done mine."

But working together is not only about riding into the sunset together. Not even if you are a self-styled cowboy like Feroz Khan. In Janasheen, his second attempt to turn his son Fardeen into the male equivalent of a sex kitten on speed (he plays a superbike racer), Khan makes sure a water body is always on hand so either his son or co-star Celina Jaitley can strip. Did Fardeen take kindly to that? "Yes, sweetheart," drawls Khan, "what do you expect him to wear on a beach? A suit?" Khan was not unduly surprised by his son's choice of career. "All I told him was that my legacy to him would be an education. I was a school dropout but I wanted him to study." Fardeen duly studied business management at the University of Massachusetts in Boston, US, duly caught the acting bug while doing a drama course and duly returned to become an actor in his father's Prem Aggan in 1998.

For Rohan and Ramesh, Kuch Na Kaho saw a quiet cementing of their relationship, fractured no doubt by parental divorce. "I got to know him a lot better after working with him," says Rohan. In the case of the Khans, says Feroz, his separation from wife Sundari was never an issue. "I frankly outgrew her, but both of us made sure it did not affect our relationship with the children," he says. The result: father and son are very good friends who can even discuss "last night's date with a wink and a smile".

Janasheen Fardeen Khan acts out father Feroz's fantasy as superbike racer prone to taking his clothes off at the smallest excuse.

"Fardeen is a bright boy, he knows his beans."

But being a star father can be tricky. Ask Suresh Oberoi, whose hyperventilating ways are seen to have damaged the initial goodwill earned by his son Vivek. Or even Roshan Sr who is stoic about his son's run of amazingly mediocre films ("He has done his job. I have done mine. Now let us see.") Khan Sr says he gives advice only when he is asked for it: "Fardeen is a bright boy. He knows his beans."

For the sons, living up to their pedigree is demanding. It is a reality that Rohan Sippy has squared up to with a film that is small, intimate and very different from anything his father has done. It is typical of Bollywood, which loves coincidences on and offscreen, that Kuch Na Kaho stars Abhishek Bachchan, who not only went to the same boarding school as Rohan (Aiglon in Switzerland) but is also the son of one of his father's favourite actors, Amitabh.

Perhaps, as Morpheus observed in The Matrix Reloaded: "I do not see a coincidence. I see providence. I see purpose." And destiny.