Shah Rukh Khan promised Karan Johar that this is the first film he would complete after Yash Johar death. Due to other delays, Shah Rukh Khan ended up completing Paheli (2005) first.
The idea of making this film struck Karan Johar while he was in London. During his trip, he saw the movie Before Sunset (2004), based on a couple who meet after parting ways. After seeing that film, he was out at a restaurant where he overheard a married couple breaking up amicably. The incident moved him and he decided to explore the idea.
In the scene where Rishi and Rhea call their spouses about making their marriage work, they part with a kiss on the cheek. Rhea turns back to go to her office, but Rishi cant be seen anywhere. Yet according to the angle she turns, Rishi should have been shown walking away from her.
When Dev is leaving for Toronto from Grand Central Station in NYC, he boards a SEPTA R1 train. SEPTA's R1 only serves Philadelphia, its suburbs and airport.