"Student of the Year’ new poster. (Twitter)
"Student of the Year’ new poster. (Twitter)

After a gap of almost two year, Kajol is back in Bollywod with Karan Johar's upcoming directorial project. 

For Karan, Kajol is a lucky charm and will be seen dancing in the disco song of his upcoming film "Student of the Year".

"Kajol is in the disco song and she has danced with the boys (Siddharth Malhotra and Varun Dhawan). Kajol's presence is very important for me. She has been there in every film of mine and she has always been lucky," The Times of India quoted Karan as saying.

Earlier, Kajol had a special appearance in Karan's 2003 film "Kal Ho Na Ho" and 2006 film "Kabhi Alvida Naa Kehna".

"In the number, Kajol will be seen doing the hook step (a primary step that is repetitively used) with the boys. Like a true professional, she wrapped up her part within a couple of hours of walking into the sets. When Kajol was shooting, everyone, including Karan, was in awe because she looked absolutely smashing," Hindustan Times quoted a source as saying.

"Yes, when Kajol was shooting her portion, I was only looking at her. Her presence is electrifying," Karan told HT.

The actress also impressed the two male actors - Varun Dhawan and Sidharth Malhotra - when she appeared on the set for the song.

"It was great, she just came on the sets, picked up the steps in 10 to 15 minutes, while we had been learning the steps for seven days. We actually felt for the first time, the star power," Siddharth told TOI.

"Basically when she was on the set no one saw us. We were like dancers, everyone was like 'Kajol ma'am is coming'," added Varun, son of filmmaker David Dhawan.

The hit '80s song "Disco Deewane" sung by Pakistani singer Nazia Hassan and produced by Biddu has been recreated for "Student of the Year".

The songs has been modified by music director Vishal Shekhar and sung by Sunidhi Chauhan, but some portions from song have been kept intact.