It sounds like you're referring to — the 2003 Indian sci-fi film starring Hrithik Roshan and Preity Zinta.

Koi Mil Gaya is a 2003 Indian science fiction romantic drama film directed by Rakesh Omprakash Mehra. The movie features Shah Rukh Khan, Preity Zinta, and Irrfan Khan in lead roles. The film's unique blend of science fiction, romance, and drama made it a massive hit among audiences worldwide.