The actress appears alongside Imran in the love triangle comedy Mere Brother Ki Dulhan.
She told DNA: "He looks like Aamir, he sounds like him. At times I feel it is Aamir and not Imran that I am sitting with and talking to. It freaks me out completely."
The actress also revealed that she had to be told how to hold a marijuana cigarette in the film.
She said: "Imran and Ali both don't smoke cigarettes, let alone beedi. So there is no way that they would have taught me to hold a beedi. It was actually [choreographer] Bosco who taught me to hold it while shooting the song."
In the film, she is also seen playing guitar, dressed as a rock musician.
"I learnt 10% from Ali [Zafar, singer] and the rest 90% Farhan [Akhtar] taught me. Ali was so impatient with me. After playing for just five minutes, he'd expect me to play like a rockstar. I couldn't do that," she admitted.
She was gifted a guitar by Zindagi Na Milegri Dobara co-star Farhan Akhtar in preparation for the role.
In May, Khan said that he would love Kaif to do an item number in Delhi Belly.
Watch the trailer for Mere Brother Ki Dulhan below: