Bollywood actor Ali Fazal will replace Arjun Rampal in Soni Razdan`s directorial venture `Love Affair`, a film on infidelity in marriage. The film also stars Kalki Koechlin, Gulshan Devaiah and Monica Dongra. Ali confirms he had been approached to replace Arjun Rampal due to some issues. He agreed to play the part as it is quite challenging, and has since immersed himself to figure out the looks and costumes of the film. Karishma Kotak has been replaced by Kalki in the lead female role. Ali will play Kalki`s husband and Gulshan will be seen in the role of her lover.