"We are great friends and colleagues, and soon we have a film coming up called 'Kapoor and Sons'," Sidharth told PTI.
"We (Alia and I) have a great working relationship. I know her since my first film, so there is an emotional connect. We have always been there for each other's films. We knew each other before we did films so that bond never changes," the 31-year-old actor said.
On various occasions, from film screenings to parties and events, Sidharth and Alia have been often seen together.
Initially, media reports used to affect Sidharth's family, but now the actor says they are getting used to it.
"We all are professionals and we know how to work for the film or a scene. Initially it used to affect my family, they are in Delhi...they were not aware about all this...how and what is written. They used to question. We are getting trained and used to it," the actor said.
Sidharth and Alia made their acting debut with Karan Johar's "Student of the Year". Now they have teamed up again for Johar's romantic drama "Kapoor and Sons", directed by Shakun Batra. Also starring Pakistani actor Fawad Khan in the lead, the film will hit the cinema houses on March 18.
The 'Ek Villain' actor feels there has been a drastic change in Alia as an actress.
"I think 'Student of the Year' was the least that she got...'Highway' took her to another level and from there she has gone up. You see that in front of the camera," he said.
"There is a remarkable change in her as an actor...the way she enacts a scene and all," Sidharth said.
The actor says in 'Kapoor and Sons' their characters will not explore the romantic angle.
" It ('Kapoor and Sons') is not a proper love story.
Hopefully, we will do a love story in the future. It is a love story, but it is about a family. It is not just about these two people alone, but about others like parents, brothers, grandparents and all," he said.
"It is about the whole family...slightly dysfunctional modern family. There is a love story, but not a pure love story," he added.