Answer
The answer is "Andaz", a 1949 romantic musical drama film directed by Mehboob Khan. It marked the beginning of Kapoor's transition from lead to supporting roles. The film revolves around a love triangle involving Kapoor, Dilip Kumar, and Nargis, with Kapoor playing a pivotal supporting character. The film's success solidified Kapoor's status as one of the most versatile actors of Indian cinema.