Prem (Ranbir) is a happy go lucky fun loving chap staying in a small town. But problems follow him everywhere even when he is all set to do something good for others. Prem along with his friends runs a ‘Happy Club’ which believes in joining hearts of lovers. Following some misunderstandings, Prem loses his heart to new girl in town Jenny (Katrina). He finds out she is an orphan staying with a heartless family. Prem’s friends motivate him to tell her his ‘dil ki baat’ and he tries all his level best to match Jenny’s choices. After a month long gap of staying away from Jenny he is finally all set to tell her his feelings, he finds her house locked and family migrated to Goa to forcibly marry her to a cash rich idiot. He goes to Goa to seek her but only to be shocked by her revelation that she loves one Rahul (Upen) and wants to elope and get married to him. Heartbroken but not dejected, Prem decides to bring the two lovers together. But complications arise further. What chaos it all leads to as Prem goes all out to make the Jenny-Rahul marriage happen, forms the rest of this fun filled entertainer.

Ajab Prem ki Ghazab Kahani” is a romantic love story packed with lots of laughs. Ranbir Kapoor is paired against Katrina Kaif and Salman khan is also included as a special guest role. Upen Patel, Asrani, Lalit Parashar, and Darshan Jariwala make up the rest of the star cast. The movie has been Produced by Ramesh S Taurani and directed by Rajkumar Santoshi. It  released under the banner ‘Tips Music Films’, on November 6, 2009. Irshad kamil has written the lyrics and the music is given by Pritam Chakraborty.

Ranbir Kapoor has acted in 8 different looks in this film. Inspired by Sanjeev Kumar who had got 9 different looks in “Naya Din Nayi Raat”, Ranbir Kapoor has also intend to do something similar in this film including the pathanwala, halwaiwala, a corporate officer etc. He has even donned Charlie Chaplin in this film. Shyamli, a renowned Indian costume designer has styled Ranbir’s costume.

From someone who is not ready to move an inch, a hardly-working vagabond, Prem becomes someone who starts working hard to make money. Maturity takes place of gullibility and he turns into a man who puts his love’s (Jenny’s) happiness above everything else.

The film is set in a comic book setting so the reality is bound to be a tad crazy. The film then depicts each prisoner’s story brilliantly and realistically.