It is the first time the duo, who share a close friendship in real life, are teaming up for a project.
Wishing Aishwarya a happy 42nd birthday, Johar tweeted today, "It's been absolutely wonderful working with her!!! Happy birthday to the stunning Aishwariya..."
Johar is currently filming the romantic drama with Aishwarya, Ranbir Kapoor and Anushka Sharma.
The movie that dwells on inter-personal relationships is set for a box-office clash on October 28 next year with Ajya Devgn's "Shivaay".