The actress will take on the role of a rural girl who falls in love with a man's scent.
Mukerji told Bollywood Hungama: "I don't know why they say that it's a comeback film, because when Aamir [Khan] comes [back] with his film after a year or a year and a half, nobody calls his film a comeback film.
"But I guess... that they miss me so much that they want to see me immediately. So I take it as a compliment."
The romantic comedy is directed by debutant filmmaker Sachin Kundalkar.
"I love working with new directors, especially directors who have seen my body of work and want to experiment and make me look different on screen," added Mukerji.
"They've seen all my work and they feel, 'Okay, we've seen Rani like this so far, now let's bring out something new in Rani'."
Mukerji said recently that actresses in Bollywood do not have a shorter shelf life than their male co-stars.
She will be also be seen in the psychological thriller Talaash opposite Aamir Khan.
Watch the trailer for Aiyyaa below: