The rumours of the cast had been doing the rounds for sometime, but Karan, who is producing the film under his banner Dharma Productions, took to Twitter to finally confirm the details.
"A modern family film with a love triangle embedded in it...KAPOOR and SONS directed by @shakunbatra," he tweeted.
In another post, he added: "KAPOOR and SONS starring @S1dharthM @_fawadakhan_ @aliaa08 and @chintskap @KapoorAndSons @DharmaMovies."
Batra's directorial debut "Ek Main Aur Ekk Tu" was also produced by Karan, while Alia and Sidharth's debut film "Student Of The Year" was produced and directed by Karan too.
Meanwhile, the multi-faceted Karan - actor, director, producer, screen writer, costume designer and TV personality - also announced that the cast of his other production, the remake of 1989 blockbuster film "Ram Lakhan", is yet to be finalised.
Karan wrote: "While Rohit (director Rohit Shetty) and I are extremely excited with the excitement RAM LAKHAN has generated....we would like to say...IT HAS NOT BEEN CAST!!!"