The real-reel formula has been tried and tested over the years though it hasn't always seen success at the box office. Filmmakers, nevertheless, don't tire of trying to portray the blood-is-thicker-than-water premise on screen.

Last week audience got to see the Shetty sisters - Shilpa and Shamita - fighting over Manoj Bajpai attention in Deepak Tijori's "Fareb".

Audience had been waiting patiently to see Amitabh Bachchan play father to son Abhishek on screen. Ram Gopal Varma's "Sarkar" pulled off the casting coup and how!

Sunny and Bobby Deol played brothers in Sunny's directorial debut "Dillagi" in 1999. The 'historic' coming-together didn't create even a remote ripple at the box office.

When Shahid Kapur's mom Neelima Azim appeared in her real-life role in "Ishq Vishq" in 2003, there were mild titters among the audience.

From the time cinema came on to its own, parents have desisted sharing screen space with children and siblings have stayed away from flattering comparisons with their kid-siblings.

Dev Anand played his own son Suniel's dad in "Anand Aur Anand". The film sank without a trace.

Sanjay Leela Bhansali had first offered the mother-daughter roles in "Khamoshi: The Musical" to Dimple Kapadia and her daughter Twinkle.

"Take Twinkle and sign someone else for the mother's role," Dimple had suggested.

Sanjay preferred Seema Biswas and Manisha Koirala.

The legendary Nutan must have flinched when she had agreed to play her son Mohnish Behl's mother in a horrific 'social' drama called "Yeh Kaisa Farz". And Sharmila Tagore was Saif Ali Khan's mother in his debut film "Aashiq Awaara". But the mothers would have forgiven the on-screen disasters.

Illustrious parents have largely stayed away from sharing the same frame as their children.

The most glaring exception was Randhir Kapoor's "Kal Aaj Aur Kal" in 1971 where Prithviraj Kapoor, Raj Kapoor and Randhir Kapoor appeared as grandfather, father and son - the relations they shared in real life. Babita (who later married Randhir aka Daboo) pitched in as the junior-most Kapoor's love interest.

But siblings in the same frame have not always worked.

There can be no better example than Dharmesh Darshan's "Mela" where Aamir Khan deigned to duet with his real-life sibling Faizal.

The 'sagaa' (blood relations) saga sagged swifter than the stock market.

Meanwhile "Pyar Kiya To Darna Kya", where Arbaaz Khan was cast as Salman's brother-in-law, clicked. But "Hello Brother", where the two did a personality-transference ghost trick, bombed.

Now all three Khan brothers - Salman, Sohail and Arbaaz - will be seen in David Dhawan's "Maine Pyar Kyun Kiya".

The legendary Dilip Kumar and his elder brother Nasir Khan worked as warring siblings in Nitin Bose's "Ganga Jumna". But no one knew he was the thespian's brother.

Now with the media keeping audiences abreast of the star's entire family tree you can't fool audiences into believing Shilpa and Shamita can be rivals in love... or can you?

No wonder Hema Malini is in two minds about a long-pending project where she gets to play her own daughter's mother.