This was the second collaboration between Rakesh Roshan and Hrithik Roshan after Kaho Na… Pyaar Hai (2000)
The film drew comparisons to Steven Spielberg’s E.T. the Extra-Terrestrial (1982). “Koi… Mil Gaya is not an Indian E.T,' Rakesh Roshan had stated at the time.Indravadan Purohit with an animatronic headgear. The actor died in 2014.Rishi Kapoor and Anil Kapoor were approached to play Hrithik’s father, eventually played by Rakesh Roshan himself.The role of Nisha was initially offered to Aishwarya Rai. It went to Preity Zinta after she declined.Rohit’s father dies in a car crash in the start. The same incident happened in Preity Zinta’s life.Preity and Hrithik had previously worked in Mission Kashmir.Rohit undergoes a drastic physical transformation in the film. Since Hrithik couldn’t lose weight so quickly, baggy clothes and a special hairstyle was crafted for the look.The film was shot in Kasauli and Nainital. Shooting also took place in Canada.For Rohit, Hrithik used the same pair of glasses that he wore as Raj in Kaho Na Pyaar Hai.The character of Jaadu was revived in the TV spin-off J Bole Toh Jaadoo.The film was initially titled Koi Aap Jaisa.The makers had shot two different endings. In the alternate ending, the alien takes away all the powers with him.The music the scientists use to communicate with the aliens is from Trans-Europe Express by Kraftwerk.Jadoo's costumes and animatronics head were designed by Australian artist James Colmer.For his character, Hrithik took inspiration from “Weird Al' YankovicThe film had many product placements: Avon Cycle, Bournvita, Camlin geometry box, Hero Honda bike, Coca-Cola.The bullying scene with the cycle was reportedly taken from Hrithik’s own childhood.Hrithik was the first actor to win both Best Actor Critics and Best Actor at the Filmfare Awards for Koi... Mil Gaya.Koi… Mil Gaya won the National Film Award for Best Film on Other Social Issues.The film spawned two sequels: Krrish and Krrish 3. A fourth installment has been announced.Singers Udit Narayan and Alka Yagnik voiced the main songs in the film.The dance number, It’s Magic, was voiced by Taz (Tarsame Singh Saini)Since 1987, all of Rakesh Roshan’s directorials begin with the letter K.Koi Mil Gaya, made on a budget of 30 crores, made 80+ crores at the box office.