Earlier this month, news broke that Shraddha had been signed to play the female lead in the movie, which is an official adaptation of Chetan Bhagat's novel of the same name.
Arjun said he is preparing for his character and will start shooting for the film soon.
"I've committed to doing 'Half Girlfriend'. I am prepping for it for the next two and a half months and then start it," Arjun said in an interview.
"Half Girlfriend" is a love story of a Bihari boy and an upper society girl. Based on the backdrop of how English defines a class system, it talks about Madhav, who wants a relationship with the high society, urban and English speaking Riya, but the girl is not interested in commitment. Hence she becomes his half girlfriend.
The movie is expected to go on floors this year and will be shot in varied locations from Bihar, Delhi to New York.
Meanwhile, Arjun is excited as he is set to make his TV debut as the host of the new season of "Khatron Ke Khiladi".
"I was very excited when they offered me the show. I did ask them why me.. They said it's a fact that I am young enough to evolve into any format they need me to be. It was very exciting for me that they thought I was mouldable."
The actor, however, said his biggest fear was if he could host a show successfully as it is a big challenge.
"My biggest fear was will I able to host... I used to fear if I can interact (as a host) but even that isn't there anymore. Hosting is a challenging thing because you have to be yourself. When you are doing a film you masquerade as a character. As a host I am just Arjun Kapoor while staying honest and entertaining at the same time."
The reality game show, based on Americas "Fear Factor", was previously hosted by Akshay Kumar, Priyanka Chopra and Rohit Shetty.
